Eric Pop

All Publications

• Energy-Efficient Phase-Change Memory with Graphene as a Thermal Barrier NANO LETTERS Ahn, C., Fong, S. W., Kim, Y., Lee, S., Sood, A., Neumann, C. M., Ashegh, M., Goodson, K. E., Pop, E., Wong, H. P. 2015; 15 (10): 6809-6814

  View details for DOI 10.1021/acs.nanolett.5b02661

  View details for Web of Science ID 000363003100079

• Nanoscale phase change memory with graphene ribbon electrodes APPLIED PHYSICS LETTERS Behnam, A., Xiong, F., Cappelli, A., Wang, N. C., Carrion, E. A., Hong, S., Dai, Y., Lyons, A. S., Chow, E. K., Piccinini, E., Jacoboni, C., Pop, E. 2015; 107 (12)

  View details for DOI 10.1063/1.4931491

  View details for Web of Science ID 000361832600072

• Forward-bias diode parameters, electronic noise, and photoresponse of graphene/silicon Schottky junctions with an interfacial native oxide layer JOURNAL OF APPLIED PHYSICS An, Y., Behnam, A., Pop, E., Bosman, G., Ural, A. 2015; 118 (11)

  View details for DOI 10.1063/1.4931142

  View details for Web of Science ID 000361843300022

• A Compact Virtual-Source Model for Carbon Nanotube FETs in the Sub-10-nm Regime-Part II: Extrinsic Elements, Performance Assessment, and Design Optimization IEEE TRANSACTIONS ON ELECTRON DEVICES Lee, C., Pop, E., Franklin, A. D., Haensch, W., Wong, H. P. 2015; 62 (9): 3070-3078

  View details for DOI 10.1109/TED.2015.2457424

  View details for Web of Science ID 000360401500057

• A Compact Virtual-Source Model for Carbon Nanotube FETs in the Sub-10-nm Regime-Part I: Intrinsic Elements IEEE TRANSACTIONS ON ELECTRON DEVICES Lee, C., Pop, E., Franklin, A. D., Haensch, W., Wong, H. P. 2015; 62 (9): 3061-3069

  View details for DOI 10.1109/TED.2015.2457453

  View details for Web of Science ID 000360401500056

• Graphene-Based Platform for Infrared Near-Field Nanospectroscopy of Water and Biological Materials in an Aqueous Environment. ACS nano Khatib, O., Wood, J. D., McLeod, A. S., Goldflam, M. D., Wagner, M., Damhorst, G. L., Koepke, J. C., Doidge, G. P., Rangarajan, A., Bashir, R., Pop, E., Lyding, J. W., Thiemens, M. H., Keilmann, F., Basov, D. N. 2015; 9 (8): 7968-7975

  Abstract

  Scattering scanning near-field optical microscopy (s-SNOM) has emerged as a powerful nanoscale spectroscopic tool capable of characterizing individual biomacromolecules and molecular materials. However, applications of scattering-based near-field techniques in the infrared (IR) to native biosystems still await a solution of how to implement the required aqueous environment. In this work, we demonstrate an IR-compatible liquid cell architecture that enables near-field imaging and nanospectroscopy by taking advantage of the unique properties of graphene. Large-area graphene acts as an impermeable monolayer barrier that allows for nano-IR inspection of underlying molecular materials in liquid. Here, we use s-SNOM to investigate the tobacco mosaic virus (TMV) in water underneath graphene. We resolve individual virus particles and register the amide I and II bands of TMV at ca. 1520 and 1660 cm(-1), respectively, using nanoscale Fourier transform infrared spectroscopy (nano-FTIR). We verify the presence of water in the graphene liquid cell by identifying a spectral feature associated with water absorption at 1610 cm(-1).

  View details for DOI 10.1021/acsnano.5b01184

  View details for PubMedID 26223158

• Graphene-Based Platform for Infrared Near-Field Nanospectroscopy of Water and Biological Materials in an Aqueous Environment ACS NANO Khatib, O., Wood, J. D., McLeod, A. S., Goldflam, M. D., Wagner, M., Damhorst, G. L., Koepke, J. C., Doidge, G. P., Rangarajan, A., Bashir, R., Pop, E., Lyding, J. W., Thiemens, M. H., Keilmann, F., Basov, D. N. 2015; 9 (8): 7968-7975

  View details for DOI 10.1021/acsnano.5b01184

  View details for Web of Science ID 000360323300025

• Bright visible light emission from graphene NATURE NANOTECHNOLOGY Kim, Y. D., Kim, H., Cho, Y., Ryoo, J. H., Park, C., Kim, P., Kim, Y. S., Lee, S., Li, Y., Park, S., Yoo, Y. S., Yoon, D., Dorgan, V. E., Pop, E., Heinz, T. F., Hone, J., Chun, S., Cheong, H., Lee, S. W., Bae, M., Park, Y. D. 2015; 10 (8): 676-681

  Abstract

  Graphene and related two-dimensional materials are promising candidates for atomically thin, flexible and transparent optoelectronics. In particular, the strong light-matter interaction in graphene has allowed for the development of state-of-the-art photodetectors, optical modulators and plasmonic devices. In addition, electrically biased graphene on SiO2 substrates can be used as a low-efficiency emitter in the mid-infrared range. However, emission in the visible range has remained elusive. Here, we report the observation of bright visible light emission from electrically biased suspended graphene devices. In these devices, heat transport is greatly reduced. Hot electrons (∼2,800 K) therefore become spatially localized at the centre of the graphene layer, resulting in a 1,000-fold enhancement in thermal radiation efficiency. Moreover, strong optical interference between the suspended graphene and substrate can be used to tune the emission spectrum. We also demonstrate the scalability of this technique by realizing arrays of chemical-vapour-deposited graphene light emitters. These results pave the way towards the realization of commercially viable large-scale, atomically thin, flexible and transparent light emitters and displays with low operation voltage and graphene-based on-chip ultrafast optical communications.

  View details for DOI 10.1038/NNANO.2015.118

  View details for Web of Science ID 000359754500010

• Solution-Mediated Selective Nanosoldering of Carbon Nanotube Junctions for Improved Device Performance ACS NANO Do, J., Chang, N. N., Estrada, D., Lian, F., Cha, H., Duan, X. J., Haasch, R. T., Pop, E., Girolami, G. S., Lyding, J. W. 2015; 9 (5): 4806-4813

  Abstract

  As-grown randomly aligned networks of carbon nanotubes (CNTs) invariably suffer from limited transport properties due to high resistance at the crossed junctions between CNTs. In this work, Joule heating of the highly resistive CNT junctions is carried out in the presence of a spin-coated layer of a suitable chemical precursor. The heating triggers thermal decomposition of the chemical precursor, tris(dibenzylideneacetone)dipalladium (Pd2(dba)3), and causes local deposition of Pd nanoparticles at the CNT junctions, thereby improving the on/off current ratio and mobility of CNT network devices by an average factor of ∼6. This process can be conducted either in air or under vacuum depending on the characteristics of the precursor species. The solution-mediated nanosoldering process is simple, fast, scalable with manufacturing techniques, and extendable to the nanodeposition of a wide variety of materials.

  View details for DOI 10.1021/nn505552d

  View details for Web of Science ID 000355383000017

  View details for PubMedID 25844819

• Annealing free, clean graphene transfer using alternative polymer scaffolds NANOTECHNOLOGY Wood, J. D., Doidge, G. P., Carrion, E. A., Koepke, J. C., Kaitz, J. A., Datye, I., Behnam, A., Hewaparakrama, J., Aruin, B., Chen, Y., Dong, H., Haasch, R. T., Lyding, J. W., Pop, E. 2015; 26 (5)

  Abstract

  We examine the transfer of graphene grown by chemical vapor deposition (CVD) with polymer scaffolds of poly(methyl methacrylate) (PMMA), poly(lactic acid) (PLA), poly(phthalaldehyde) (PPA), and poly(bisphenol A carbonate) (PC). We find that optimally reactive PC scaffolds provide the cleanest graphene transfers without any annealing, after extensive comparison with optical microscopy, x-ray photoelectron spectroscopy, atomic force microscopy, and scanning tunneling microscopy. Comparatively, films transferred with PLA, PPA, PMMA/PC, and PMMA have a two-fold higher roughness and a five-fold higher chemical doping. Using PC scaffolds, we demonstrate the clean transfer of CVD multilayer graphene, fluorinated graphene, and hexagonal boron nitride. Our annealing free, PC transfers enable the use of atomically-clean nanomaterials in biomolecule encapsulation and flexible electronic applications.

  View details for DOI 10.1088/0957-4484/26/5/055302

  View details for Web of Science ID 000347952000010

  View details for PubMedID 25580991

• Scaling of graphene integrated circuits NANOSCALE Bianchi, M., Guerriero, E., Fiocco, M., Alberti, R., Polloni, L., Behnam, A., Carrion, E. A., Pop, E., Sordan, R. 2015; 7 (17): 8076-8083

  Abstract

  The influence of transistor size reduction (scaling) on the speed of realistic multi-stage integrated circuits (ICs) represents the main performance metric of a given transistor technology. Despite extensive interest in graphene electronics, scaling efforts have so far focused on individual transistors rather than multi-stage ICs. Here we study the scaling of graphene ICs based on transistors from 3.3 to 0.5 μm gate lengths and with different channel widths, access lengths, and lead thicknesses. The shortest gate delay of 31 ps per stage was obtained in sub-micron graphene ROs oscillating at 4.3 GHz, which is the highest oscillation frequency obtained in any strictly low-dimensional material to date. We also derived the fundamental Johnson limit, showing that scaled graphene ICs could be used at high frequencies in applications with small voltage swing.

  View details for DOI 10.1039/c5nr01126d

  View details for Web of Science ID 000353981700067

  View details for PubMedID 25873359

• Direct observation of resistive heating at graphene wrinkles and grain boundaries APPLIED PHYSICS LETTERS Grosse, K. L., Dorgan, V. E., Estrada, D., Wood, J. D., Vlassiouk, I., Eres, G., Lyding, J. W., King, W. P., Pop, E. 2014; 105 (14)

  View details for DOI 10.1063/1.4896676

  View details for Web of Science ID 000344343900053

• Heterogeneous nanometer-scale Joule and Peltier effects in sub-25 nm thin phase change memory devices JOURNAL OF APPLIED PHYSICS Grosse, K. L., Pop, E., King, W. P. 2014; 116 (12)

  View details for DOI 10.1063/1.4896492

  View details for Web of Science ID 000342840000089

• Nanometer-scale temperature imaging for independent observation of Joule and Peltier effects in phase change memory devices REVIEW OF SCIENTIFIC INSTRUMENTS Grosse, K. L., Pop, E., King, W. P. 2014; 85 (9)

  View details for DOI 10.1063/1.4895715

  View details for Web of Science ID 000342910500062

• Phase change materials and phase change memory MRS BULLETIN Raoux, S., Xiong, F., Wuttig, M., Pop, E. 2014; 39 (8): 703-710

  View details for DOI 10.1557/mrs.2014.139

  View details for Web of Science ID 000341107900012

• Theoretical analysis of high-field transport in graphene on a substrate JOURNAL OF APPLIED PHYSICS Serov, A. Y., Ong, Z., Fischetti, M. V., Pop, E. 2014; 116 (3)

  View details for DOI 10.1063/1.4884614

  View details for Web of Science ID 000340710500085

• Substrate-supported thermometry platform for nanomaterials like graphene, nanotubes, and nanowires APPLIED PHYSICS LETTERS Li, Z., Bae, M., Pop, E. 2014; 105 (2)

  View details for DOI 10.1063/1.4887365

  View details for Web of Science ID 000341151400065

• Ultrafast terahertz-induced response of GeSbTe phase-change materials APPLIED PHYSICS LETTERS Shu, M. J., Zalden, P., Chen, F., Weems, B., Chatzakis, I., Xiong, F., Jeyasingh, R., Hoffmann, M. C., Pop, E., Wong, H. P., Wuttig, M., Lindenberg, A. M. 2014; 104 (25)

  View details for DOI 10.1063/1.4884816

  View details for Web of Science ID 000338515900032

• Monolithic III-V Nanowire Solar Cells on Graphene via Direct van der Waals Epitaxy ADVANCED MATERIALS Mohseni, P. K., Behnam, A., Wood, J. D., Zhao, X., Yu, K. J., Wang, N. C., Rockett, A., Rogers, J. A., Lyding, J. W., Pop, E., Li, X. 2014; 26 (22): 3755-3760

  View details for DOI 10.1002/adma.201305909

  View details for Web of Science ID 000337688400025

  View details for PubMedID 24652703

• Self-Aligned Cu Etch Mask for Individually Addressable Metallic and Semiconducting Carbon Nanotubes ACS NANO Jiang, Y., Xiong, F., Tsai, C., Ozel, T., Pop, E., Shim, M. 2014; 8 (6): 6500-6508

  View details for DOI 10.1021/nn502390r

  View details for Web of Science ID 000338089200120

• Hysteresis-Free Nanosecond Pulsed Electrical Characterization of Top-Gated Graphene Transistors IEEE TRANSACTIONS ON ELECTRON DEVICES Carrion, E. A., Serov, A. Y., Islam, S., Behnam, A., Malik, A., Xiong, F., Bianchi, M., Sordan, R., Pop, E. 2014; 61 (5): 1583-1589

  View details for DOI 10.1109/TED.2014.2309651

  View details for Web of Science ID 000337753300054

• Carbon Nanotube Circuit Integration up to Sub-20 nm Channel Lengths ACS NANO Shulaker, M. M., Van Rethy, J., Wu, T. F., Liyanage, L. S., Wei, H., Li, Z., Pop, E., Gielen, G., Wong, H. P., Mitra, S. 2014; 8 (4): 3434-3443

  Abstract

  Carbon nanotube (CNT) field-effect transistors (CNFETs) are a promising emerging technology projected to achieve over an order of magnitude improvement in energy-delay product, a metric of performance and energy efficiency, compared to silicon-based circuits. However, due to substantial imperfections inherent with CNTs, the promise of CNFETs has yet to be fully realized. Techniques to overcome these imperfections have yielded promising results, but thus far only at large technology nodes (1 μm device size). Here we demonstrate the first very large scale integration (VLSI)-compatible approach to realizing CNFET digital circuits at highly scaled technology nodes, with devices ranging from 90 nm to sub-20 nm channel lengths. We demonstrate inverters functioning at 1 MHz and a fully integrated CNFET infrared light sensor and interface circuit at 32 nm channel length. This demonstrates the feasibility of realizing more complex CNFET circuits at highly scaled technology nodes.

  View details for DOI 10.1021/nn406301r

  View details for Web of Science ID 000334990600034

• Nanoscale thermal transport. II. 2003-2012 APPLIED PHYSICS REVIEWS Cahill, D. G., Braun, P. V., Chen, G., Clarke, D. R., Fan, S., Goodson, K. E., Keblinski, P., King, W. P., Mahan, G. D., Majumdar, A., Maris, H. J., Phillpot, S. R., Pop, E., Shi, L. 2014; 1 (1)

  View details for DOI 10.1063/1.4832615

  View details for Web of Science ID 000334098500010

• High-Field and Thermal Transport in 2D Atomic Layer Devices MICRO- AND NANOTECHNOLOGY SENSORS, SYSTEMS, AND APPLICATIONS VI Serov, A., Dorgan, V. E., Behnam, A., English, C. D., Li, Z., Islam, S., Pop, E. 2014; 9083

  View details for DOI 10.1117/12.2052093

  View details for Web of Science ID 000342426300004

• Energy Efficiency and Conversion in 1D and 2D Electronics PROCEEDINGS OF THE 2014 44TH EUROPEAN SOLID-STATE DEVICE RESEARCH CONFERENCE (ESSDERC 2014) Pop, E., English, C., Xiong, F., Lian, F., Serov, A., Li, Z., Islam, S., Dorgan, V. 2014: 35-37

  View details for Web of Science ID 000348858100006

• Multi-Valley Hi :h-Field Transport in 2-Dimensional MoS2 Transistors 2014 72ND ANNUAL DEVICE RESEARCH CONFERENCE (DRC) Serov, A. Y., Dorgan, V. E., English, C. D., Pop, E. 2014: 183-184

  View details for Web of Science ID 000346309800084

• Improving Contact Resistance in MoS2 Field Effect Transistors 2014 72ND ANNUAL DEVICE RESEARCH CONFERENCE (DRC) English, C. D., Shine, G., Dorgan, V. E., Saraswat, K. C., Pop, E. 2014: 193-194

  View details for Web of Science ID 000346309800089

• Variability of Graphene Mobility and Contacts: Surface Effects, Doping and Strain 2014 72ND ANNUAL DEVICE RESEARCH CONFERENCE (DRC) Carrion, E. A., Wood, J. D., Behman, A., Tung, M., Lyding, J. W., Pop, E. 2014: 199-200

  View details for Web of Science ID 000346309800092

• Nanosoldering Carbon Nanotube Junctions by Local Chemical Vapor Deposition for Improved Device Performance NANO LETTERS Do, J., Estrada, D., Xie, X., Chang, N. N., Mallek, J., Girolami, G. S., Rogers, J. A., Pop, E., Lyding, J. W. 2013; 13 (12): 5844-5850

  Abstract

  The performance of carbon nanotube network (CNN) devices is usually limited by the high resistance of individual nanotube junctions (NJs). We present a novel method to reduce this resistance through a nanoscale chemical vapor deposition (CVD) process. By passing current through the devices in the presence of a gaseous CVD precursor, localized nanoscale Joule heating induced at the NJs stimulates the selective and self-limiting deposition of metallic nanosolder. The effectiveness of this nanosoldering process depends on the work function of the deposited metal (here Pd or HfB2), and it can improve the on/off current ratio of a CNN device by nearly an order of magnitude. This nanosoldering technique could also be applied to other device types where nanoscale resistance components limit overall device performance.

  View details for DOI 10.1021/nl4026083

  View details for Web of Science ID 000328439200014

  View details for PubMedID 24215439

• Helical Carbon Nanotubes Enhance the Early Immune Response and Inhibit Macrophage-Mediated Phagocytosis of Pseudomonas aeruginosa PLOS ONE Walling, B. E., Kuang, Z., Hao, Y., Estrada, D., Wood, J. D., Lian, F., Miller, L. A., Shah, A. B., Jeffries, J. L., Haasch, R. T., Lyding, J. W., Pop, E., Lau, G. W. 2013; 8 (11)

  Abstract

  Aerosolized or aspirated manufactured carbon nanotubes have been shown to be cytotoxic, cause pulmonary lesions, and demonstrate immunomodulatory properties. CD-1 mice were used to assess pulmonary toxicity of helical carbon nanotubes (HCNTs) and alterations of the immune response to subsequent infection by Pseudomonas aeruginosa in mice. HCNTs provoked a mild inflammatory response following either a single exposure or 2X/week for three weeks (multiple exposures) but were not significantly toxic. Administering HCNTs 2X/week for three weeks resulted in pulmonary lesions including granulomas and goblet cell hyperplasia. Mice exposed to HCNTs and subsequently infected by P. aeruginosa demonstrated an enhanced inflammatory response to P. aeruginosa and phagocytosis by alveolar macrophages was inhibited. However, clearance of P. aeruginosa was not affected. HCNT exposed mice depleted of neutrophils were more effective in clearing P. aeruginosa compared to neutrophil-depleted control mice, accompanied by an influx of macrophages. Depletion of systemic macrophages resulted in slightly inhibited bacterial clearance by HCNT treated mice. Our data indicate that pulmonary exposure to HCNTs results in lesions similar to those caused by other nanotubes and pre-exposure to HCNTs inhibit alveolar macrophage phagocytosis of P. aeruginosa. However, clearance was not affected as exposure to HCNTs primed the immune system for an enhanced inflammatory response to pulmonary infection consisting of an influx of neutrophils and macrophages.

  View details for DOI 10.1371/journal.pone.0080283

  View details for Web of Science ID 000327308500124

  View details for PubMedID 24324555

• High field breakdown characteristics of carbon nanotube thin film transistors NANOTECHNOLOGY Gupta, M. P., Behnam, A., Lian, F., Estrada, D., Pop, E., Kumar, S. 2013; 24 (40)

  Abstract

  The high field properties of carbon nanotube (CNT) network thin film transistors (CN-TFTs) are important for their practical operation, and for understanding their reliability. Using a combination of experimental and computational techniques we show how the channel geometry (length LC and width WC) and network morphology (average CNT length Lt and alignment angle distribution θ) affect heat dissipation and high field breakdown in such devices. The results suggest that when WC ≥ Lt, the breakdown voltage remains independent of WC but varies linearly with LC. The breakdown power varies almost linearly with both WC and LC when WC ≫ Lt. We also find that the breakdown power is more susceptible to the variability in the network morphology compared to the breakdown voltage. The analysis offers new insight into the tunable heat dissipation and thermal reliability of CN-TFTs, which can be significantly improved through optimization of the network morphology and device geometry.

  View details for DOI 10.1088/0957-4484/24/40/405204

  View details for Web of Science ID 000324516300006

  View details for PubMedID 24029606

• High-Field Electrical and Thermal Transport in Suspended Graphene NANO LETTERS Dorgan, V. E., Behnam, A., Conley, H. J., Bolotin, K. I., Pop, E. 2013; 13 (10): 4581-4586

  Abstract

  We study the intrinsic transport properties of suspended graphene devices at high fields (≥1 V/μm) and high temperatures (≥1000 K). Across 15 samples, we find peak (average) saturation velocity of 3.6 × 10(7) cm/s (1.7 × 10(7) cm/s) and peak (average) thermal conductivity of 530 W m(-1) K(-1) (310 W m(-1) K(-1)) at 1000 K. The saturation velocity is 2-4 times and the thermal conductivity 10-17 times greater than in silicon at such elevated temperatures. However, the thermal conductivity shows a steeper decrease at high temperature than in graphite, consistent with stronger effects of second-order three-phonon scattering. Our analysis of sample-to-sample variation suggests the behavior of "cleaner" devices most closely approaches the intrinsic high-field properties of graphene. This study reveals key features of charge and heat flow in graphene up to device breakdown at ~2230 K in vacuum, highlighting remaining unknowns under extreme operating conditions.

  View details for DOI 10.1021/nl400197w

  View details for Web of Science ID 000326356300001

  View details for PubMedID 23387323

• Conductive preferential paths of hot carriers in amorphous phase-change materials APPLIED PHYSICS LETTERS Cappelli, A., Piccinini, E., Xiong, F., Behnam, A., Brunetti, R., Rudan, M., Pop, E., Jacoboni, C. 2013; 103 (8)

  View details for DOI 10.1063/1.4819097

  View details for Web of Science ID 000323788100085

• Compact Model for Carbon Nanotube Field-Effect Transistors Including Nonidealities and Calibrated With Experimental Data Down to 9-nm Gate Length IEEE TRANSACTIONS ON ELECTRON DEVICES Luo, J., Wei, L., Lee, C., Franklin, A. D., Guan, X., Pop, E., Antoniadis, D. A., Wong, H. P. 2013; 60 (6): 1834-1843

  View details for DOI 10.1109/TED.2013.2258023

  View details for Web of Science ID 000319355500006

• Gigahertz Integrated Graphene Ring Oscillators ACS NANO Guerriero, E., Polloni, L., Bianchi, M., Behnam, A., Carrion, E., Rizzi, L. G., Pop, E., Sordan, R. 2013; 7 (6): 5588-5594

  Abstract

  Ring oscillators (ROs) are the most important class of circuits used to evaluate the performance limits of any digital technology. However, ROs based on low-dimensional nanomaterials (e.g., 1-D nanotubes, nanowires, 2-D MoS2) have so far exhibited limited performance due to low current drive or large parasitics. Here we demonstrate integrated ROs fabricated from wafer-scale graphene grown by chemical vapor deposition. The highest oscillation frequency was 1.28 GHz, while the largest output voltage swing was 0.57 V. Both values remain limited by parasitic capacitances in the circuit rather than intrinsic properties of the graphene transistor components, suggesting further improvements are possible. The fabricated ROs are the fastest realized in any low-dimensional nanomaterial to date and also the least sensitive to fluctuations in the supply voltage. They represent the first integrated graphene oscillators of any kind and can also be used in a wide range of applications in analog electronics. As a demonstration, we also realized the first stand-alone graphene mixers that do not require external oscillators for frequency conversion. The first gigahertz multitransistor graphene integrated circuits demonstrated here pave the way for application of graphene in high-speed digital and analog circuits in which high operating speed could be traded off against power consumption.

  View details for DOI 10.1021/nn401933v

  View details for Web of Science ID 000321093800098

  View details for PubMedID 23713626

• Resistive Random Access Memory Enabled by Carbon Nanotube Crossbar Electrodes ACS NANO Tsai, C., Xiong, F., Pop, E., Shim, M. 2013; 7 (6): 5360-5366

  Abstract

  We use single-walled carbon nanotube (CNT) crossbar electrodes to probe sub-5 nm memory domains of thin AlOx films. Both metallic and semiconducting CNTs effectively switch AlOx bits between memory states with high and low resistance. The low-resistance state scales linearly with CNT series resistance down to ∼10 MΩ, at which point the ON-state resistance of the AlOx filament becomes the limiting factor. Dependence of switching behavior on the number of cross-points suggests a single channel to dominate the overall characteristics in multi-crossbar devices. We demonstrate ON/OFF ratios up to 5 × 10(5) and programming currents of 1 to 100 nA with few-volt set/reset voltages. Remarkably low reset currents enable a switching power of 10-100 nW and estimated switching energy as low as 0.1-10 fJ per bit. These results are essential for understanding the ultimate scaling limits of resistive random access memory at single-nanometer bit dimensions.

  View details for DOI 10.1021/nn401212p

  View details for Web of Science ID 000321093800072

  View details for PubMedID 23705675

• Direct observation of nanometer-scale Joule and Peltier effects in phase change memory devices APPLIED PHYSICS LETTERS Grosse, K. L., Xiong, F., Hong, S., King, W. P., Pop, E. 2013; 102 (19)

  View details for DOI 10.1063/1.4803172

  View details for Web of Science ID 000320440800100

• Signatures of dynamic screening in interfacial thermal transport of graphene PHYSICAL REVIEW B Ong, Z., Fischetti, M. V., Serov, A. Y., Pop, E. 2013; 87 (19)

  View details for DOI 10.1103/PhysRevB.87.195404

  View details for Web of Science ID 000318519300004

• The Role of External Defects in Chemical Sensing of Graphene Field-Effect Transistors NANO LETTERS Kumar, B., Min, K., Bashirzadeh, M., Farimani, A. B., Bae, M., Estrada, D., Kim, Y. D., YASAEI, P., Park, Y. D., Pop, E., Aluru, N. R., Salehi-Khojin, A. 2013; 13 (5): 1962-1968

  Abstract

  A fundamental understanding of chemical sensing mechanisms in graphene-based chemical field-effect transistors (chemFETs) is essential for the development of next generation chemical sensors. Here we explore the hidden sensing modalities responsible for tailoring the gas detection ability of pristine graphene sensors by exposing graphene chemFETs to electron donor and acceptor trace gas vapors. We uncover that the sensitivity (in terms of modulation in electrical conductivity) of pristine graphene chemFETs is not necessarily intrinsic to graphene, but rather it is facilitated by external defects in the insulating substrate, which can modulate the electronic properties of graphene. We disclose a mixing effect caused by partial overlap of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of adsorbed gas molecules to explain graphene's ability to detect adsorbed molecules. Our results open a new design space, suggesting that control of external defects in supporting substrates can lead to tunable graphene chemical sensors, which could be developed without compromising the intrinsic electrical and structural properties of graphene.

  View details for DOI 10.1021/nl304734g

  View details for Web of Science ID 000318892400015

  View details for PubMedID 23586702

• Using nanoscale thermocapillary flows to create arrays of purely semiconducting single-walled carbon nanotubes NATURE NANOTECHNOLOGY Jin, S. H., Dunham, S. N., Song, J., Xie, X., Kim, J., Lu, C., Islam, A., Du, F., Kim, J., Felts, J., Li, Y., Xiong, F., Wahab, M. A., Menon, M., Cho, E., Grosse, K. L., Lee, D. J., Chung, H. U., Pop, E., Alam, M. A., King, W. P., Huang, Y., Rogers, J. A. 2013; 8 (5): 347-355

  Abstract

  Among the remarkable variety of semiconducting nanomaterials that have been discovered over the past two decades, single-walled carbon nanotubes remain uniquely well suited for applications in high-performance electronics, sensors and other technologies. The most advanced opportunities demand the ability to form perfectly aligned, horizontal arrays of purely semiconducting, chemically pristine carbon nanotubes. Here, we present strategies that offer this capability. Nanoscale thermocapillary flows in thin-film organic coatings followed by reactive ion etching serve as highly efficient means for selectively removing metallic carbon nanotubes from electronically heterogeneous aligned arrays grown on quartz substrates. The low temperatures and unusual physics associated with this process enable robust, scalable operation, with clear potential for practical use. We carry out detailed experimental and theoretical studies to reveal all of the essential attributes of the underlying thermophysical phenomena. We demonstrate use of the purified arrays in transistors that achieve mobilities exceeding 1,000 cm(2) V(-1) s(-1) and on/off switching ratios of ∼10,000 with current outputs in the milliamp range. Simple logic gates built using such devices represent the first steps toward integration into more complex circuits.

  View details for DOI 10.1038/NNANO.2013.56

  View details for Web of Science ID 000318684800017

  View details for PubMedID 23624697

• Ballistic to diffusive crossover of heat flow in graphene ribbons NATURE COMMUNICATIONS Bae, M., Li, Z., Aksamija, Z., Martin, P. N., Xiong, F., Ong, Z., Knezevic, I., Pop, E. 2013; 4

  Abstract

  Heat flow in nanomaterials is an important area of study, with both fundamental and technological implications. However, little is known about heat flow in two-dimensional devices or interconnects with dimensions comparable to the phonon mean free path. Here we find that short, quarter-micron graphene samples reach ~35% of the ballistic thermal conductance limit up to room temperature, enabled by the relatively large phonon mean free path (~100 nm) in substrate-supported graphene. In contrast, patterning similar samples into nanoribbons leads to a diffusive heat-flow regime that is controlled by ribbon width and edge disorder. In the edge-controlled regime, the graphene nanoribbon thermal conductivity scales with width approximately as ~W(1.8)(0.3), being about 100 W m(-1) K(-1) in 65-nm-wide graphene nanoribbons, at room temperature. These results show how manipulation of two-dimensional device dimensions and edges can be used to achieve full control of their heat-carrying properties, approaching fundamentally limited upper or lower bounds.

  View details for DOI 10.1038/ncomms2755

  View details for Web of Science ID 000318872100091

  View details for PubMedID 23591901

• InxGa1-xAs Nanowire Growth on Graphene: van der Waals Epitaxy Induced Phase Segregation NANO LETTERS Mohseni, P. K., Behnam, A., Wood, J. D., English, C. D., Lyding, J. W., Pop, E., Li, X. 2013; 13 (3): 1153-1161

  Abstract

  The growth of high-density arrays of vertically oriented, single crystalline InAs NWs on graphene surfaces are realized through the van der Waals (vdW) epitaxy mechanism by metalorganic chemical vapor deposition (MOCVD). However, the growth of InGaAs NWs on graphene results in spontaneous phase separation starting from the beginning of growth, yielding a well-defined InAs-In(x)Ga(1-x)As (0.2 < x < 1) core-shell structure. The core-shell structure then terminates abruptly after about 2 μm in height, and axial growth of uniform composition In(x)Ga(1-x)As takes place without a change in the NW diameter. The In(x)Ga(1-x)As shell composition changes as a function of indium flow, but the core and shell thicknesses and the onset of nonsegregated In(x)Ga(1-x)As axial segment are independent of indium composition. In contrast, no InGaAs phase segregation has been observed when growing on MoS2, another two-dimensional (2D) layered material, or via the Au-assisted vapor-liquid-solid (VLS) mechanism on graphene. This spontaneous phase segregation phenomenon is elucidated as a special case of van der Waals epitaxy on 2D sheets. Considering the near lattice matched registry between InAs and graphene, InGaAs is forced to self-organize into InAs core and InGaAs shell segments since the lack of dangling bonds on graphene does not allow strain sharing through elastic deformation between InGaAs and graphene.

  View details for DOI 10.1021/nl304569d

  View details for Web of Science ID 000316243800045

  View details for PubMedID 23421807

• Role of Joule Heating on Current Saturation and Transient Behavior of Graphene Transistors IEEE ELECTRON DEVICE LETTERS Islam, S., Li, Z., Dorgan, V. E., Bae, M., Pop, E. 2013; 34 (2): 166-168

  View details for DOI 10.1109/LED.2012.2230393

  View details for Web of Science ID 000314173200006

• Self-Aligned Nanotube-Nanowire Phase Change Memory NANO LETTERS Xiong, F., Bae, M., Dai, Y., Liao, A. D., Behnam, A., Carrion, E. A., Hong, S., Ielmini, D., Pop, E. 2013; 13 (2): 464-469

  Abstract

  A central issue of nanoelectronics concerns their fundamental scaling limits, that is, the smallest and most energy-efficient devices that can function reliably. Unlike charge-based electronics that are prone to leakage at nanoscale dimensions, memory devices based on phase change materials (PCMs) are more scalable, storing digital information as the crystalline or amorphous state of a material. Here, we describe a novel approach to self-align PCM nanowires with individual carbon nanotube (CNT) electrodes for the first time. The highly scaled and spatially confined memory devices approach the ultimate scaling limits of PCM technology, achieving ultralow programming currents (~0.1 μA set, ~1.6 μA reset), outstanding on/off ratios (~10(3)), and improved endurance and stability at few-nanometer bit dimensions. In addition, the powerful yet simple nanofabrication approach described here can enable confining and probing many other nanoscale and molecular devices self-aligned with CNT electrodes.

  View details for DOI 10.1021/nl3038097

  View details for Web of Science ID 000315079500022

  View details for PubMedID 23259592

• Effect of grain boundaries on thermal transport in graphene APPLIED PHYSICS LETTERS Serov, A. Y., Ong, Z., Pop, E. 2013; 102 (3)

  View details for DOI 10.1063/1.4776667

  View details for Web of Science ID 000314032600068

• Metal-semiconductor-metal photodetectors based on graphene/p-type silicon Schottky junctions APPLIED PHYSICS LETTERS An, Y., Behnam, A., Pop, E., Ural, A. 2013; 102 (1)

  View details for DOI 10.1063/1.4773992

  View details for Web of Science ID 000313646500104

• Atomic-Scale Evidence for Potential Barriers and Strong Carrier Scattering at Graphene Grain Boundaries: A Scanning Tunneling Microscopy Study ACS NANO Koepke, J. C., Wood, J. D., Estrada, D., Ong, Z., He, K. T., Pop, E., Lyding, J. W. 2013; 7 (1): 75-86

  Abstract

  We use scanning tunneling microscopy and spectroscopy to examine the electronic nature of grain boundaries (GBs) in polycrystalline graphene grown by chemical vapor deposition (CVD) on Cu foil and transferred to SiO(2) substrates. We find no preferential orientation angle between grains, and the GBs are continuous across graphene wrinkles and SiO(2) topography. Scanning tunneling spectroscopy shows enhanced empty states tunneling conductance for most of the GBs and a shift toward more n-type behavior compared to the bulk of the graphene. We also observe standing wave patterns adjacent to GBs propagating in a zigzag direction with a decay length of ~1 nm. Fourier analysis of these patterns indicates that backscattering and intervalley scattering are the dominant mechanisms responsible for the mobility reduction in the presence of GBs in CVD-grown graphene.

  View details for DOI 10.1021/nn302064p

  View details for Web of Science ID 000314082800012

  View details for PubMedID 23237026

• Substrate Dependent High-Field Transport of Graphene Transistors 2013 71ST ANNUAL DEVICE RESEARCH CONFERENCE (DRC) Islam, S., Serov, A. Y., Meric, I., Shepard, K. L., Pop, E. 2013: 35-36

  View details for Web of Science ID 000347466000026

• Realistic Simulation of Graphene Transistors Including Non-Ideal Electrostatics 2013 71ST ANNUAL DEVICE RESEARCH CONFERENCE (DRC) Serov, A. Y., Islam, S., Pop, E. 2013: 31-32

  View details for Web of Science ID 000347466000024

• Reliability, Failure, and Fundamental Limits of Graphene and Carbon Nanotube Interconnects 2013 IEEE INTERNATIONAL ELECTRON DEVICES MEETING (IEDM) Liao, A. D., Behnam, A., Dorgan, V. E., Li, Z., Pop, E. 2013

  View details for Web of Science ID 000346509500096

• Novel 3D random-network model for threshold switching of phase-change memories 2013 IEEE INTERNATIONAL ELECTRON DEVICES MEETING (IEDM) Piccinini, E., Cappelli, A., Xiong, F., Behnam, A., Buscemi, F., Brunetti, R., Rudan, M., Pop, E., Jacoboni, C. 2013

  View details for Web of Science ID 000346509500149

• High-Field Transport and Thermal Reliability of Sorted Carbon Nanotube Network Devices ACS NANO Behnam, A., Sangwan, V. K., Zhong, X., Lian, F., Estrada, D., Jariwala, D., Hoag, A. J., Lauhon, L. J., Marks, T. J., Hersam, M. C., Pop, E. 2013; 7 (1): 482-490

  Abstract

  We examine the high-field operation, power dissipation, and thermal reliability of sorted carbon nanotube network (CNN) devices, with <1% to >99% semiconducting nanotubes. We combine systematic electrical measurements with infrared (IR) thermal imaging and detailed Monte Carlo simulations to study high-field transport up to CNN failure by unzipping-like breakdown. We find that metallic CNNs carry peak current densities up to an order of magnitude greater than semiconducting CNNs at comparable nanotube densities. Metallic CNNs also appear to have a factor of 2 lower intrinsic thermal resistance, suggesting a lower thermal resistance at metallic nanotube junctions. The performance limits and reliability of CNNs depend on their makeup, and could be improved by carefully engineered heat dissipation through the substrate, contacts, and nanotube junctions. These results are essential for optimization of CNN devices on transparent or flexible substrates which typically have very low thermal conductivity.

  View details for DOI 10.1021/nn304570u

  View details for Web of Science ID 000314082800052

  View details for PubMedID 23259715

• Electrochemistry at the Edge of a Single Graphene Layer in a Nanopore ACS NANO Banerjee, S., Shim, J., Rivera, J., Jin, X., Estrada, D., Solovyeva, V., You, X., Pak, J., Pop, E., Aluru, N., Bashir, R. 2013; 7 (1): 834-843

  Abstract

  We study the electrochemistry of single layer graphene edges using a nanopore-based structure consisting of stacked graphene and Al(2)O(3) dielectric layers. Nanopores, with diameters ranging from 5 to 20 nm, are formed by an electron beam sculpting process on the stacked layers. This leads to a unique edge structure which, along with the atomically thin nature of the embedded graphene electrode, demonstrates electrochemical current densities as high as 1.2 × 10(4) A/cm(2). The graphene edge embedded structure offers a unique capability to study the electrochemical exchange at an individual graphene edge, isolated from the basal plane electrochemical activity. We also report ionic current modulation in the nanopore by biasing the embedded graphene terminal with respect to the electrodes in the fluid. The high electrochemical specific current density for a graphene nanopore-based device can have many applications in sensitive chemical and biological sensing, and energy storage devices.

  View details for DOI 10.1021/nn305400n

  View details for Web of Science ID 000314082800091

  View details for PubMedID 23249127

• Impact of thermal boundary conductances on power dissipation and electrical breakdown of carbon nanotube network transistors JOURNAL OF APPLIED PHYSICS Gupta, M. P., Chen, L., Estrada, D., Behnam, A., Pop, E., Kumar, S. 2012; 112 (12)

  View details for DOI 10.1063/1.4767920

  View details for Web of Science ID 000312829400129

• Thermal properties of graphene: Fundamentals and applications MRS BULLETIN Pop, E., Varshney, V., Roy, A. K. 2012; 37 (12): 1273-1281

  View details for DOI 10.1557/mrs.2012.203

  View details for Web of Science ID 000311491900016

• Quantitative Thermal Imaging of Single-Walled Carbon Nanotube Devices by Scanning Joule Expansion Microscopy ACS NANO Xie, X., Grosse, K. L., Song, J., Lu, C., Dunham, S., Du, F., Islam, A. E., Li, Y., Zhang, Y., Pop, E., Huang, Y., King, W. P., Rogers, J. A. 2012; 6 (11): 10267-10275

  Abstract

  Electrical generation of heat in single-walled carbon nanotubes (SWNTs) and subsequent thermal transport into the surroundings can critically affect the design, operation, and reliability of electronic and optoelectronic devices based on these materials. Here we investigate such heat generation and transport characteristics in perfectly aligned, horizontal arrays of SWNTs integrated into transistor structures. We present quantitative assessments of local thermometry at individual SWNTs in these arrays, evaluated using scanning Joule expansion microscopy. Measurements at different applied voltages reveal electronic behaviors, including metallic and semiconducting responses, spatial variations in diameter or chirality, and localized defect sites. Analytical models, validated by measurements performed on different device structures at various conditions, enable accurate, quantitative extraction of temperature distributions at the level of individual SWNTs. Using current equipment, the spatial resolution and temperature precision are as good as ∼100 nm and ∼0.7 K, respectively.

  View details for DOI 10.1021/nn304083a

  View details for Web of Science ID 000311521700101

  View details for PubMedID 23061768

• Transport in Nanoribbon Interconnects Obtained from Graphene Grown by Chemical Vapor Deposition NANO LETTERS Behnam, A., Lyons, A. S., Bae, M., Chow, E. K., Islam, S., Neumann, C. M., Pop, E. 2012; 12 (9): 4424-4430

  Abstract

  We study graphene nanoribbon (GNR) interconnects obtained from graphene grown by chemical vapor deposition (CVD). We report low- and high-field electrical measurements over a wide temperature range, from 1.7 to 900 K. Room temperature mobilities range from 100 to 500 cm(2)·V(-1)·s(-1), comparable to GNRs from exfoliated graphene, suggesting that bulk defects or grain boundaries play little role in devices smaller than the CVD graphene crystallite size. At high-field, peak current densities are limited by Joule heating, but a small amount of thermal engineering allows us to reach ∼2 × 10(9) A/cm(2), the highest reported for nanoscale CVD graphene interconnects. At temperatures below ∼5 K, short GNRs act as quantum dots with dimensions comparable to their lengths, highlighting the role of metal contacts in limiting transport. Our study illustrates opportunities for CVD-grown GNRs, while revealing variability and contacts as remaining future challenges.

  View details for DOI 10.1021/nl300584r

  View details for Web of Science ID 000308576000002

  View details for PubMedID 22853618

• Cascading Wafer-Scale Integrated Graphene Complementary Inverters under Ambient Conditions NANO LETTERS Rizzi, L. G., Bianchi, M., Behnam, A., Carrion, E., Guerriero, E., Polloni, L., Pop, E., Sordan, R. 2012; 12 (8): 3948-3953

  Abstract

  The fundamental building blocks of digital electronics are logic gates which must be capable of cascading such that more complex logic functions can be realized. Here we demonstrate integrated graphene complementary inverters which operate with the same input and output voltage logic levels, thus allowing cascading. We obtain signal matching under ambient conditions with inverters fabricated from wafer-scale graphene grown by chemical vapor deposition (CVD). Monolayer graphene was incorporated in self-aligned field-effect transistors in which the top gate overlaps with the source and drain contacts. This results in full-channel gating and leads to the highest low-frequency voltage gain reported so far in top-gated CVD graphene devices operating in air ambient, A(v) ∼ -5. Such gain enabled logic inverters with the same voltage swing of 0.56 V at their input and output. Graphene inverters could find their way in realistic applications where high-speed operation is desired but power dissipation is not a concern, similar to emitter-coupled logic.

  View details for DOI 10.1021/nl301079r

  View details for Web of Science ID 000307211000013

  View details for PubMedID 22793169

• Scanning Tunneling Microscopy Study and Nanomanipulation of Graphene-Coated Water on Mica NANO LETTERS He, K. T., Wood, J. D., Doidge, G. P., Pop, E., Lyding, J. W. 2012; 12 (6): 2665-2672

  Abstract

  We study interfacial water trapped between a sheet of graphene and a muscovite (mica) surface using Raman spectroscopy and ultrahigh vacuum scanning tunneling microscopy (UHV-STM) at room temperature. We are able to image the graphene-water interface with atomic resolution, revealing a layered network of water trapped underneath the graphene. We identify water layer numbers with a carbon nanotube height reference. Under normal scanning conditions, the water structures remain stable. However, at greater electron energies, we are able to locally manipulate the water using the STM tip.

  View details for DOI 10.1021/nl202613t

  View details for Web of Science ID 000305106400003

  View details for PubMedID 22612064

• Effect of Carbon Nanotube Network Morphology on Thin Film Transistor Performance NANO RESEARCH Timmermans, M. Y., Estrada, D., Nasibulin, A. G., Wood, J. D., Behnam, A., Sun, D., Ohno, Y., Lyding, J. W., Hassanien, A., Pop, E., Kauppinen, E. I. 2012; 5 (5): 307-319

  View details for DOI 10.1007/s12274-012-0211-8

  View details for Web of Science ID 000304114100002

• Effects of tip-nanotube interactions on atomic force microscopy imaging of carbon nanotubes NANO RESEARCH Alizadegan, R., Liao, A. D., Xiong, F., Pop, E., Hsia, K. J. 2012; 5 (4): 235-247

  View details for DOI 10.1007/s12274-012-0203-8

  View details for Web of Science ID 000303408100002

• Nanometalization of single-wall carbon nanotubes and graphene quantum dots ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY Ye, W., Martin, P. A., Kumar, N., Estrada, D., Daly, S. R., Rockett, A. A., Abelson, J. R., Pop, E., Girolami, G. S., Lyding, J. W. 2012; 243

  View details for Web of Science ID 000324503201307

• New Technique of DNA Sensing: Nanoribbon Transverse Electrodes BIOPHYSICAL JOURNAL Solovyeva, V., Chow, E., Bae, M., Estrada, D., Banerjee, S., Behnam, A., Dorgan, V. E., Chang, W., Pop, E., Bashir, R. 2012; 102 (3): 428A-428A

  View details for Web of Science ID 000321561203044

• Chemical sensors based on randomly stacked graphene flakes APPLIED PHYSICS LETTERS Salehi-Khojin, A., Estrada, D., Lin, K. Y., Ran, K., Haasch, R. T., Zuo, J., Pop, E., Masel, R. I. 2012; 100 (3)

  View details for DOI 10.1063/1.3676276

  View details for Web of Science ID 000299386800049

• Atomic-scale Study of Scattering and Electronic Properties of CVD Graphene Grain Boundaries 2012 12TH IEEE CONFERENCE ON NANOTECHNOLOGY (IEEE-NANO) Koepke, J. C., Wood, J. D., Estrada, D., Ong, Z., Xiong, F., Pop, E., Lyding, J. W. 2012

  View details for Web of Science ID 000309933900222

• IMPACT OF CONTACT RESISTANCES ON ELECTRICAL AND THERMAL TRANSPORT IN CARBON NANOTUBE NETWORK TRANSISTORS PROCEEDINGS OF THE ASME MICRO/NANOSCALE HEAT AND MASS TRANSFER INTERNATIONAL CONFERENCE, 2012 Gupta, M. P., Estrada, D., Pop, E., Kumar, S. 2012: 769-776

  View details for Web of Science ID 000324346800098

• Scanning Tunneling Microscopy Characterization of Graphene-coated Few-layered Water on Mica 2012 12TH IEEE CONFERENCE ON NANOTECHNOLOGY (IEEE-NANO) He, K. T., Wood, J. D., Doidge, G. P., Pop, E., Lyding, J. W. 2012

  View details for Web of Science ID 000309933900084

• Nanosoldering Carbon Nanotube Junctions with Metal via Local Chemical Vapor Deposition for Improved Device Performance 2012 12TH IEEE CONFERENCE ON NANOTECHNOLOGY (IEEE-NANO) Do, J., Estrada, D., Xie, X., Chang, N. N., Girolami, G. S., Rogers, J. A., Pop, E., Lyding, J. W. 2012

  View details for Web of Science ID 000309933900217

• Graphene Nanopores for Nucleic Acid Analysis 2012 12TH IEEE CONFERENCE ON NANOTECHNOLOGY (IEEE-NANO) Shim, J., Solovyeva, V., Estrada, D., Banerjee, S., Rivera, J., Pop, E., Bashir, R. 2012

  View details for Web of Science ID 000309933900351

• Improved Graphene Growth and Fluorination on Cu with Clean Transfer to Surfaces 2012 12TH IEEE CONFERENCE ON NANOTECHNOLOGY (IEEE-NANO) Wood, J. D., Schmucker, S. W., Raasch, R. T., Doidge, G. P., Nienhaus, L., Damhorst, G. L., Lyons, A. S., Gruebele, M., Bashir, R., Pop, E., Lyding, J. W. 2012

  View details for Web of Science ID 000309933900216

• Stacked Graphene-Al2O3 Nanopore Sensors for Sensitive Detection of DNA and DNA-Protein Complexes ACS NANO Venkatesan, B. M., Estrada, D., Banerjee, S., Jin, X., Dorgan, V. E., Bae, M., Aluru, N. R., Pop, E., Bashir, R. 2012; 6 (1): 441-450

  Abstract

  We report the development of a multilayered graphene-Al(2)O(3) nanopore platform for the sensitive detection of DNA and DNA-protein complexes. Graphene-Al(2)O(3) nanolaminate membranes are formed by sequentially depositing layers of graphene and Al(2)O(3), with nanopores being formed in these membranes using an electron-beam sculpting process. The resulting nanopores are highly robust, exhibit low electrical noise (significantly lower than nanopores in pure graphene), are highly sensitive to electrolyte pH at low KCl concentrations (attributed to the high buffer capacity of Al(2)O(3)), and permit the electrical biasing of the embedded graphene electrode, thereby allowing for three terminal nanopore measurements. In proof-of-principle biomolecule sensing experiments, the folded and unfolded transport of single DNA molecules and RecA-coated DNA complexes could be discerned with high temporal resolution. The process described here also enables nanopore integration with new graphene-based structures, including nanoribbons and nanogaps, for single-molecule DNA sequencing and medical diagnostic applications.

  View details for DOI 10.1021/nn203769e

  View details for Web of Science ID 000299368300054

  View details for PubMedID 22165962

• Polycrystalline Graphene Ribbons as Chemiresistors ADVANCED MATERIALS Salehi-Khojin, A., Estrada, D., Lin, K. Y., Bae, M., Xiong, F., Pop, E., Masel, R. I. 2012; 24 (1): 53-?

  View details for DOI 10.1002/adma.201102663

  View details for Web of Science ID 000298602300004

  View details for PubMedID 22113971

• Pressure tuning of the thermal conductance of weak interfaces PHYSICAL REVIEW B Hsieh, W., Lyons, A. S., Pop, E., Keblinski, P., Cahill, D. G. 2011; 84 (18)

  View details for DOI 10.1103/PhysRevB.84.184107

  View details for Web of Science ID 000297101700004

• A Web Service and Interface for Remote Electronic Device Characterization IEEE TRANSACTIONS ON EDUCATION Dutta, S., Prakash, S., Estrada, D., Pop, E. 2011; 54 (4): 646-651

  View details for DOI 10.1109/TE.2011.2105488

  View details for Web of Science ID 000296478700017

• Effects of Polycrystalline Cu Substrate on Graphene Growth by Chemical Vapor Deposition NANO LETTERS Wood, J. D., Schmucker, S. W., Lyons, A. S., Pop, E., Lyding, J. W. 2011; 11 (11): 4547-4554

  Abstract

  Chemical vapor deposition of graphene on Cu often employs polycrystalline Cu substrates with diverse facets, grain boundaries (GBs), annealing twins, and rough sites. Using scanning electron microscopy (SEM), electron-backscatter diffraction (EBSD), and Raman spectroscopy on graphene and Cu, we find that Cu substrate crystallography affects graphene growth more than facet roughness. We determine that (111) containing facets produce pristine monolayer graphene with higher growth rate than (100) containing facets, especially Cu(100). The number of graphene defects and nucleation sites appears Cu facet invariant at growth temperatures above 900 °C. Engineering Cu to have (111) surfaces will cause monolayer, uniform graphene growth.

  View details for DOI 10.1021/nl201566c

  View details for Web of Science ID 000296674700008

  View details for PubMedID 21942318

• Reduction of phonon lifetimes and thermal conductivity of a carbon nanotube on amorphous silica PHYSICAL REVIEW B Ong, Z., Pop, E., Shiomi, J. 2011; 84 (16)

  View details for DOI 10.1103/PhysRevB.84.165418

  View details for Web of Science ID 000298991800010

• Scaling of High-Field Transport and Localized Heating in Graphene Transistors ACS NANO Bae, M., Islam, S., Dorgan, V. E., Pop, E. 2011; 5 (10): 7936-7944

  Abstract

  We use infrared thermal imaging and electrothermal simulations to find that localized Joule heating in graphene field-effect transistors on SiO(2) is primarily governed by device electrostatics. Hot spots become more localized (i.e., sharper) as the underlying oxide thickness is reduced, such that the average and peak device temperatures scale differently, with significant long-term reliability implications. The average temperature is proportional to oxide thickness, but the peak temperature is minimized at an oxide thickness of ∼90 nm due to competing electrostatic and thermal effects. We also find that careful comparison of high-field transport models with thermal imaging can be used to shed light on velocity saturation effects. The results shed light on optimizing heat dissipation and reliability of graphene devices and interconnects.

  View details for DOI 10.1021/nn202239y

  View details for Web of Science ID 000296208700042

  View details for PubMedID 21913673

• Electronic, optical and thermal properties of the hexagonal and rocksalt-like Ge2Sb2Te5 chalcogenide from first-principle calculations JOURNAL OF APPLIED PHYSICS Tsafack, T., Piccinini, E., Lee, B., Pop, E., Rudan, M. 2011; 110 (6)

  View details for DOI 10.1063/1.3639279

  View details for Web of Science ID 000295619300071

• Stretchable, Transparent Graphene Interconnects for Arrays of Microscale Inorganic Light Emitting Diodes on Rubber Substrates NANO LETTERS Kim, R., Bae, M., Kim, D. G., Cheng, H., Kim, B. H., Kim, D., Li, M., Wu, J., Du, F., Kim, H., Kim, S., Estrada, D., Hong, S. W., Huang, Y., Pop, E., Rogers, J. A. 2011; 11 (9): 3881-3886

  Abstract

  This paper describes the fabrication and design principles for using transparent graphene interconnects in stretchable arrays of microscale inorganic light emitting diodes (LEDs) on rubber substrates. We demonstrate several appealing properties of graphene for this purpose, including its ability to spontaneously conform to significant surface topography, in a manner that yields effective contacts even to deep, recessed device regions. Mechanics modeling reveals the fundamental aspects of this process, as well as the use of the same layers of graphene for interconnects designed to accommodate strains of 100% or more, in a completely reversible fashion. These attributes are compatible with conventional thin film processing and can yield high-performance devices in transparent layouts. Graphene interconnects possess attractive features for both existing and emerging applications of LEDs in information display, biomedical systems, and other environments.

  View details for DOI 10.1021/nl202000u

  View details for Web of Science ID 000294790200064

  View details for PubMedID 21790143

• Effect of substrate modes on thermal transport in supported graphene PHYSICAL REVIEW B Ong, Z., Pop, E. 2011; 84 (7)

  View details for DOI 10.1103/PhysRevB.84.075471

  View details for Web of Science ID 000293830600027

• Electrical power dissipation in semiconducting carbon nanotubes on single crystal quartz and amorphous SiO2 APPLIED PHYSICS LETTERS Tsai, C., liao, A., Pop, E., Shim, M. 2011; 99 (5)

  View details for DOI 10.1063/1.3622769

  View details for Web of Science ID 000293617300082

• Thermally Limited Current Carrying Ability of Graphene Nanoribbons PHYSICAL REVIEW LETTERS Liao, A. D., Wu, J. Z., Wang, X., Tahy, K., Jena, D., Dai, H., Pop, E. 2011; 106 (25)

  Abstract

  We investigate high-field transport in graphene nanoribbons (GNRs) on SiO(2), up to breakdown. The maximum current density is limited by self-heating, but can reach >3 mA/?m for GNRs ~15 nm wide. Comparison with larger, micron-sized graphene devices reveals that narrow GNRs benefit from 3D heat spreading into the SiO(2), which enables their higher current density. GNRs also benefit from lateral heat flow to the contacts in short devices (<~0.3 ?m), which allows extraction of a median GNR thermal conductivity (TC), ~80 W m(-1)K(-1) at 20 °C across our samples, dominated by phonons. The TC of GNRs is an order of magnitude lower than that of micron-sized graphene on SiO(2), suggesting strong roles of edge and defect scattering, and the importance of thermal dissipation in small GNR devices.

  View details for DOI 10.1103/PhysRevLett.106.256801

  View details for Web of Science ID 000291801900010

  View details for PubMedID 21770659

• Nanoscale Joule heating, Peltier cooling and current crowding at graphene-metal contacts NATURE NANOTECHNOLOGY Grosse, K. L., Bae, M., Lian, F., Pop, E., King, W. P. 2011; 6 (5): 287-290

  Abstract

  The performance and scaling of graphene-based electronics is limited by the quality of contacts between the graphene and metal electrodes. However, the nature of graphene-metal contacts remains incompletely understood. Here, we use atomic force microscopy to measure the temperature distributions at the contacts of working graphene transistors with a spatial resolution of ~ 10 nm (refs 5-8), allowing us to identify the presence of Joule heating, current crowding and thermoelectric heating and cooling. Comparison with simulation enables extraction of the contact resistivity (150-200 Ω µm²) and transfer length (0.2-0.5 µm) in our devices; these generally limit performance and must be minimized. Our data indicate that thermoelectric effects account for up to one-third of the contact temperature changes, and that current crowding accounts for most of the remainder. Modelling predicts that the role of current crowding will diminish and the role of thermoelectric effects will increase as contacts improve.

  View details for DOI 10.1038/NNANO.2011.39

  View details for Web of Science ID 000290301300008

  View details for PubMedID 21460825

• Low-Power Switching of Phase-Change Materials with Carbon Nanotube Electrodes SCIENCE Xiong, F., Liao, A. D., Estrada, D., Pop, E. 2011; 332 (6029): 568-570

  Abstract

  Phase-change materials (PCMs) are promising candidates for nonvolatile data storage and reconfigurable electronics, but high programming currents have presented a challenge to realize low-power operation. We controlled PCM bits with single-wall and small-diameter multi-wall carbon nanotubes. This configuration achieves programming currents of 0.5 microampere (set) and 5 microamperes (reset), two orders of magnitude lower than present state-of-the-art devices. Pulsed measurements enable memory switching with very low energy consumption. Analysis of over 100 devices finds that the programming voltage and energy are highly scalable and could be below 1 volt and single femtojoules per bit, respectively.

  View details for DOI 10.1126/science.1201938

  View details for Web of Science ID 000289991100042

  View details for PubMedID 21393510

• Imaging dissipation and hot spots in carbon nanotube network transistors APPLIED PHYSICS LETTERS Estrada, D., Pop, E. 2011; 98 (7)

  View details for DOI 10.1063/1.3549297

  View details for Web of Science ID 000287507200058

• Reliably Counting Atomic Planes of Few-Layer Graphene (n > 4) ACS NANO Koh, Y. K., Bae, M., Cahill, D. G., Pop, E. 2011; 5 (1): 269-274

  Abstract

  We demonstrate a reliable technique for counting atomic planes (n) of few-layer graphene (FLG) on SiO(2)/Si substrates by Raman spectroscopy. Our approach is based on measuring the ratio of the integrated intensity of the G graphene peak and the optical phonon peak of Si, I(G)/I(Si), and is particularly useful in the range n > 4 where few methods exist. We compare our results with atomic force microscopy (AFM) measurements and Fresnel equation calculations. Then, we apply our method to unambiguously identify n of FLG devices on SiO(2) and find that the mobility (μ ≈ 2000 cm(2) V(-1) s(-1)) is independent of layer thickness for n > 4. Our findings suggest that electrical transport in gated FLG devices is dominated by carriers near the FLG/SiO(2) interface and is thus limited by the environment, even for n > 4.

  View details for DOI 10.1021/nn102658a

  View details for Web of Science ID 000286487300034

  View details for PubMedID 21138311

• Imaging, Simulation, and Electrostatic Control of Power Dissipation in Graphene Devices NANO LETTERS Bae, M., Ong, Z., Estrada, D., Pop, E. 2010; 10 (12): 4787-4793

  View details for DOI 10.1021/nl1011596

  View details for Web of Science ID 000284990900003

• Frequency and polarization dependence of thermal coupling between carbon nanotubes and SiO2 JOURNAL OF APPLIED PHYSICS Ong, Z., Pop, E. 2010; 108 (10)

  View details for DOI 10.1063/1.3484494

  View details for Web of Science ID 000285005000042

• Thermal dissipation and variability in electrical breakdown of carbon nanotube devices PHYSICAL REVIEW B liao, A., Alizadegan, R., Ong, Z., Dutta, S., Xiong, F., Hsia, K. J., Pop, E. 2010; 82 (20)

  View details for DOI 10.1103/PhysRevB.82.205406

  View details for Web of Science ID 000283842000004

• Heat Conduction across Monolayer and Few-Layer Graphenes NANO LETTERS Koh, Y. K., Bae, M., Cahill, D. G., Pop, E. 2010; 10 (11): 4363-4368

  Abstract

  We report the thermal conductance G of Au/Ti/graphene/SiO(2) interfaces (graphene layers 1 ? n ? 10) typical of graphene transistor contacts. We find G ? 25 MW m(-2) K(-1) at room temperature, four times smaller than the thermal conductance of a Au/Ti/SiO(2) interface, even when n = 1. We attribute this reduction to the thermal resistance of Au/Ti/graphene and graphene/SiO(2) interfaces acting in series. The temperature dependence of G from 50 ? T ? 500 K also indicates that heat is predominantly carried by phonons through these interfaces. Our findings suggest that metal contacts can limit not only electrical transport but also thermal dissipation from submicrometer graphene devices.

  View details for DOI 10.1021/nl101790k

  View details for Web of Science ID 000283907600012

  View details for PubMedID 20923234

• Mobility and saturation velocity in graphene on SiO2 APPLIED PHYSICS LETTERS Dorgan, V. E., Bae, M., Pop, E. 2010; 97 (8)

  View details for DOI 10.1063/1.3483130

  View details for Web of Science ID 000281306500042

• Molecular dynamics simulation of thermal boundary conductance between carbon nanotubes and SiO2 PHYSICAL REVIEW B Ong, Z., Pop, E. 2010; 81 (15)

  View details for DOI 10.1103/PhysRevB.81.155408

  View details for Web of Science ID 000277210500107

• Covalent Functionalization and Electron-Transfer Properties of Vertically Aligned Carbon Nanofibers: The Importance of Edge-Plane Sites CHEMISTRY OF MATERIALS Landis, E. C., Klein, K. L., liao, A., Pop, E., Hensley, D. K., Melechko, A. V., Hamers, R. J. 2010; 22 (7): 2357-2366

  View details for DOI 10.1021/cm9036132

  View details for Web of Science ID 000276394800025

• Reduced Thermal Conductivity in Nanoengineered Rough Ge and GaAs Nanowires NANO LETTERS Martin, P. N., Aksamija, Z., Pop, E., Ravaioli, U. 2010; 10 (4): 1120-1124

  Abstract

  We model and compare the thermal conductivity of rough semiconductor nanowires (NWs) of Si, Ge, and GaAs for thermoelectric devices. On the basis of full phonon dispersion relations, the effect of NW surface roughness on thermal conductivity is derived from perturbation theory and appears as an efficient way to scatter phonons in Si, Ge, and GaAs NWs with diameter D < 200 nm. For small diameters and large root-mean-square roughness Delta, thermal conductivity is limited by surface asperities and varies quadratically as (D/Delta)(2). At room temperature, our model previously agreed with experimental observations of thermal conductivity down to 2 W m(-1) K(-1) in rough 56 nm Si NWs with Delta = 3 nm. In comparison to Si, we predict here remarkably low thermal conductivity in Ge and GaAs NWs of 0.1 and 0.4 W m(-1) K(-1), respectively, at similar roughness and diameter.

  View details for DOI 10.1021/nl902720v

  View details for Web of Science ID 000276557100004

  View details for PubMedID 20222669

• Energy Dissipation and Transport in Nanoscale Devices NANO RESEARCH Pop, E. 2010; 3 (3): 147-169

  View details for DOI 10.1007/s12274-010-1019-z

  View details for Web of Science ID 000275754900001

• Reduction of hysteresis for carbon nanotube mobility measurements using pulsed characterization NANOTECHNOLOGY Estrada, D., Dutta, S., liao, A., Pop, E. 2010; 21 (8)

  Abstract

  We describe a pulsed measurement technique for suppressing hysteresis for carbon nanotube (CNT) device measurements in air, vacuum, and over a wide temperature range (80-453 K). Varying the gate pulse width and duty cycle probes the relaxation times associated with charge trapping near the CNT, found to be up to the 0.1-10 s range. Longer off times between voltage pulses enable consistent, hysteresis-free measurements of CNT mobility. A tunneling front model for charge trapping and relaxation is also described, suggesting trap depths up to 4-8 nm for CNTs on SiO2. Pulsed measurements will also be applicable for other nanoscale devices such as graphene, nanowires, or molecular electronics, and could enable probing trap relaxation times in a variety of material system interfaces.

  View details for DOI 10.1088/0957-4484/21/8/085702

  View details for Web of Science ID 000273965000012

  View details for PubMedID 20097980

• Topography and refractometry of nanostructures using spatial light interference microscopy OPTICS LETTERS Wang, Z., Chun, I. S., Li, X., Ong, Z., Pop, E., Millet, L., Gillette, M., Popescu, G. 2010; 35 (2): 208-210

  Abstract

  Spatial light interference microscopy (SLIM) is a novel method developed in our laboratory that provides quantitative phase images of transparent structures with a 0.3 nm spatial and 0.03 nm temporal accuracy owing to the white light illumination and its common path interferometric geometry. We exploit these features and demonstrate SLIM's ability to perform topography at a single atomic layer in graphene. Further, using a decoupling procedure that we developed for cylindrical structures, we extract the axially averaged refractive index of semiconductor nanotubes and a neurite of a live hippocampal neuron in culture. We believe that this study will set the basis for novel high-throughput topography and refractometry of man-made and biological nanostructures.

  View details for Web of Science ID 000273879200039

  View details for PubMedID 20081970

• Infrared Imaging of Heat Dissipation in Graphene Transistors GRAPHENE, GE/III-V, AND EMERGING MATERIALS FOR POST-CMOS APPLICATIONS 2 Bae, M., Ong, Z., Estrada, D., Pop, E. 2010; 28 (5): 51-62

  View details for DOI 10.1149/1.3367936

  View details for Web of Science ID 000313494400006

• Modeling of the Voltage Snap-Back in Amorphous-GST Memory Devices SISPAD 2010 - 15TH INTERNATIONAL CONFERENCE ON SIMULATION OF SEMICONDUCTOR PROCESSES AND DEVICES Rudan, M., Giovanardi, F., Tsafack, T., Xiong, F., Piccinini, E., Buscemi, F., Liao, A., Pop, E., Brunetti, R., JACOBONI, C. 2010: 257-260

  View details for Web of Science ID 000283778800014

• Inducing chalcogenide phase change with ultra-narrow carbon nanotube heaters APPLIED PHYSICS LETTERS Xiong, F., liao, A., Pop, E. 2009; 95 (24)

  View details for DOI 10.1063/1.3273370

  View details for Web of Science ID 000272954900050

• Multiband Mobility in Semiconducting Carbon Nanotubes IEEE ELECTRON DEVICE LETTERS Zhao, Y., Liao, A., Pop, E. 2009; 30 (10): 1078-1080

  View details for DOI 10.1109/LED.2009.2027615

  View details for Web of Science ID 000270227600022

• Compact Thermal Model for Vertical Nanowire Phase-Change Memory Cells IEEE TRANSACTIONS ON ELECTRON DEVICES Chen, I., Pop, E. 2009; 56 (7): 1523-1528

  View details for DOI 10.1109/TED.2009.2021364

  View details for Web of Science ID 000267433800021

• Electrical and Thermal Coupling to a Single-Wall Carbon Nanotube Device Using an Electrothermal Nanoprobe NANO LETTERS Lee, J., liao, A., Pop, E., King, W. P. 2009; 9 (4): 1356-1361

  Abstract

  We utilize a multifunctional atomic force microscope (AFM) cantilever applying highly localized temperature and electric fields to interrogate transport in single-wall carbon nanotube field-effect transistors (CNTFETs). The probe can be operated either in contact with the CNT, in intermittent contact, or as a Kelvin probe, and can independently control the electric field, mechanical force, and temperature applied to the CNT. We modulate current flow in the CNT with tip-applied electric field, and find this field-effect depends upon both cantilever heating and CNT self-heating. CNT transport is also investigated with AFM tip temperature up to 1170 degrees C. Tip-CNT thermal resistance is estimated at 1.6 x 10(7) K/W and decreases with increasing temperature. Threshold force (<100 nN) for reliable contact mode imaging is extracted and used to determine set points for nanotube manipulation, such as displacement or cutting. The ability to measure thermal coupling to a single-molecule electronic device could offer new insights into nanoelectronic devices.

  View details for DOI 10.1021/nl803024p

  View details for Web of Science ID 000265030000014

  View details for PubMedID 19245239

• Impact of Phonon-Surface Roughness Scattering on Thermal Conductivity of Thin Si Nanowires PHYSICAL REVIEW LETTERS Martin, P., Aksamija, Z., Pop, E., Ravaioli, U. 2009; 102 (12)

  Abstract

  We present a novel approach for computing the surface roughness-limited thermal conductivity of silicon nanowires with diameter D<100 nm. A frequency-dependent phonon scattering rate is computed from perturbation theory and related to a description of the surface through the root-mean-square roughness height Delta and autocovariance length L. Using a full phonon dispersion relation, we find a quadratic dependence of thermal conductivity on diameter and roughness as (D/Delta)(2). Computed results show excellent agreement with experimental data for a wide diameter and temperature range (25-350 K), and successfully predict the extraordinarily low thermal conductivity of 2 W m(-1) K-1 at room temperature in rough-etched 50 nm silicon nanowires.

  View details for DOI 10.1103/PhysRevLett.102.125503

  View details for Web of Science ID 000264632100040

  View details for PubMedID 19392295

• A TWO-TEMPERATURE MODEL OF NARROW-BODY SILICON TRANSISTORS UNDER STEADY STATE AND TRANSIENT OPERATION PROCEEDINGS OF THE 3RD ENERGY NANOTECHNOLOGY INTERNATIONAL CONFERENCE Ong, Z., Pop, E. 2009: 97-108

  View details for Web of Science ID 000265245100016

• Infrared Microscopy of Joule Heating in Graphene Field Effect Transistors 2009 9TH IEEE CONFERENCE ON NANOTECHNOLOGY (IEEE-NANO) Bae, M., Ong, Z., Estrada, D., Pop, E. 2009: 818-821

  View details for Web of Science ID 000302997400226

• Avalanche, Joule Breakdown and Hysteresis in Carbon Nanotube Transistors 2009 IEEE INTERNATIONAL RELIABILITY PHYSICS SYMPOSIUM, VOLS 1 AND 2 Pop, E., Dutta, S., Estrada, D., liao, A. 2009: 405-408

  View details for Web of Science ID 000272068100068

• Prediction of Reduced Thermal Conductivity in Nano-Engineered Rough Semiconductor Nanowires 16TH INTERNATIONAL CONFERENCE ON ELECTRON DYNAMICS IN SEMICONDUCTORS, OPTOELECTRONICS AND NANOSTRUCTURES (EDISON 16) Martin, P. N., Aksamija, Z., Pop, E., Ravaioli, U. 2009; 193

  View details for DOI 10.1088/1742-6596/193/1/012010

  View details for Web of Science ID 000277100400010

• ELECTRON-PHONON INTERACTION AND JOULE HEATING IN NANOSTRUCTURES PROCEEDINGS OF THE 3RD ENERGY NANOTECHNOLOGY INTERNATIONAL CONFERENCE Pop, E. 2009: 129-132

  View details for Web of Science ID 000265245100020

• Comparison of Energy Relaxation in One-Dimensional Thermionic and Tunneling Transistors 2009 9TH IEEE CONFERENCE ON NANOTECHNOLOGY (IEEE-NANO) Ramasubramanian, B., Pop, E. 2009: 496-499

  View details for Web of Science ID 000302997400138

• Avalanche-Induced Current Enhancement in Semiconducting Carbon Nanotubes PHYSICAL REVIEW LETTERS liao, A., Zhao, Y., Pop, E. 2008; 101 (25)

  Abstract

  Semiconducting single-wall carbon nanotubes under high electric field stress ( approximately 10 V/mum) display a remarkable current increase due to avalanche generation of free electrons and holes. Unlike other materials, the avalanche process in such 1D quantum wires involves access to the third subband and is insensitive to temperature but strongly dependent on diameter approximately exp(-1/d;{2}). Comparison with a theoretical model yields a novel approach to obtain the inelastic optical phonon emission length lambda{OP,ems} approximately 15d nm. The new results underscore the importance of multiband transport in 1D molecular wires.

  View details for DOI 10.1103/PhysRevLett.101.256804

  View details for Web of Science ID 000261891200059

  View details for PubMedID 19113739

• The role of electrical and thermal contact resistance for Joule breakdown of single-wall carbon nanotubes NANOTECHNOLOGY Pop, E. 2008; 19 (29)

  Abstract

  Several data sets for the electrical breakdown in air of single-wall carbon nanotubes (SWNTs) on insulating substrates are collected and analyzed. A universal scaling of the Joule breakdown power with nanotube length is found, which appears to be independent of the substrate thermal properties of their thickness. This suggests that the thermal resistances at SWNT-insulator and at SWNT-electrode interfaces govern heat sinking from the nanotube. Analytical models for the breakdown power scaling are presented, providing an intuitive, physical understanding of the breakdown process. The electrical and thermal resistances at the electrode contacts limit the breakdown behavior for sub-micron SWNTs; the breakdown power scales linearly with length for tubes that are microns long, and a minimum breakdown power (∼0.05 mW) is observed for the intermediate (∼0.5 µm) length range.

  View details for DOI 10.1088/0957-4484/19/29/295202

  View details for Web of Science ID 000256838300006

  View details for PubMedID 21730598

• Thermal properties of metal-coated vertically aligned single-wall nanotube arrays JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME Panzer, M. A., Zhang, G., Mann, D., Hu, X., Pop, E., Dai, H., Goodson, K. E. 2008; 130 (5)

  View details for DOI 10.1115/1.2885159

  View details for Web of Science ID 000255880300006

• Operational voltage reduction of flash memory using high-kappa composite tunnel barriers IEEE ELECTRON DEVICE LETTERS Verma, S., Pop, E., Kapur, P., Parat, K., Saraswat, K. C. 2008; 29 (3): 252-254

  View details for DOI 10.1109/LED.2007.915376

  View details for Web of Science ID 000253441900015

• Electrically driven light emission from hot single-walled carbon nanotubes at various temperatures and ambient pressures APPLIED PHYSICS LETTERS Wang, X., Zhang, L., Lu, Y., Dai, H., Kato, Y. K., Pop, E. 2007; 91 (26)

  View details for DOI 10.1063/1.2827281

  View details for Web of Science ID 000251987400002

• Thickness and stoichiometry dependence of the thermal conductivity of GeSbTe films APPLIED PHYSICS LETTERS Reifenberg, J. P., Panzer, M. A., Kim, S., Gibby, A. M., Zhang, Y., Wong, S., Wong, H. P., Pop, E., Goodson, K. E. 2007; 91 (11)

  View details for DOI 10.1063/1.2784169

  View details for Web of Science ID 000249474000022

• Electrical and thermal transport in metallic single-wall carbon nanotubes on insulating substrates JOURNAL OF APPLIED PHYSICS Pop, E., Mann, D. A., Goodson, K. E., Dai, H. 2007; 101 (9)

  View details for DOI 10.1063/1.2717855

  View details for Web of Science ID 000246567900049

• Electrically driven thermal light emission from individual single-walled carbon nanotubes NATURE NANOTECHNOLOGY Mann, D., Kato, Y. K., Kinkhabwala, A., Pop, E., Cao, J., Wang, X., Zhang, L., Wang, Q., Guo, J., Dai, H. 2007; 2 (1): 33-38

  View details for DOI 10.1038/nnano.2006.169

  View details for Web of Science ID 000243902900012

  View details for PubMedID 18654204

• Electrical and thermal transport in metallic single-wall carbon nanotubes 2007 INTERNATIONAL SEMICONDUCTOR DEVICE RESEARCH SYMPOSIUM, VOLS 1 AND 2 Pop, E. 2007: 401-402

  View details for Web of Science ID 000255857100205

• Heat generation and transport in nanometer-scale transistors PROCEEDINGS OF THE IEEE Pop, E., Sinha, S., Goodson, K. E. 2006; 94 (8): 1587-1601

  View details for DOI 10.1109/JPROC.2006.879794

  View details for Web of Science ID 000240963400010

• Non-equilibrium phonon distributions in sub-100 nm silicon transistors JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME Sinha, S., Pop, E., DUTTON, R. W., Goodson, K. E. 2006; 128 (7): 638-647

  View details for DOI 10.1115/1.2194041

  View details for Web of Science ID 000239047600003

• Electrical transport properties and field effect transistors of carbon nanotubes NANO Dai, H., Javey, A., Pop, E., Mann, D., Kim, W., Lu, Y. 2006; 1 (1): 1-13

  View details for Web of Science ID 000202998500001

• Thermally and molecularly stimulated relaxation of hot phonons in suspended carbon nanotubes JOURNAL OF PHYSICAL CHEMISTRY B Mann, D., Pop, E., Cao, J., Wang, Q., Goodson, K. E., Dai, H. J. 2006; 110 (4): 1502-1505

  Abstract

  The high-bias electrical transport properties of suspended metallic single-walled carbon nanotubes (SWNTs) are investigated at various temperatures in vacuum, in various gases, and when coated with molecular solids. It is revealed that nonequilibrium optical phonon effects in suspended nanotubes decrease as the ambient temperature increases. Gas molecules surrounding suspended SWNTs assist the relaxation of hot phonons and afford enhanced current flow along nanotubes. Molecular solids of carbon dioxide frozen onto suspended SWNTs quench the nonequilibrium phonon effect. The discovery of strong environmental effects on high current transport in nanotubes is important to high performance nanoelectronics applications of 1D nanowires in general.

  View details for DOI 10.1021/jp0563991

  View details for Web of Science ID 000235198300002

  View details for PubMedID 16471703

• Thermal conductance of an individual single-wall carbon nanotube above room temperature NANO LETTERS Pop, E., Mann, D., Wang, Q., Goodson, K. E., Dai, H. J. 2006; 6 (1): 96-100

  Abstract

  The thermal properties of a suspended metallic single-wall carbon nanotube (SWNT) are extracted from its high-bias (I-V) electrical characteristics over the 300-800 K temperature range, achieved by Joule self-heating. The thermal conductance is approximately 2.4 nW/K, and the thermal conductivity is nearly 3500 Wm(-1)K(-1) at room temperature for a SWNT of length 2.6 mum and diameter 1.7 nm. A subtle decrease in thermal conductivity steeper than 1/T is observed at the upper end of the temperature range, which is attributed to second-order three-phonon scattering between two acoustic modes and one optical mode. We discuss sources of uncertainty and propose a simple analytical model for the SWNT thermal conductivity including length and temperature dependence.

  View details for DOI 10.1021/nl052145f

  View details for Web of Science ID 000235532400018

  View details for PubMedID 16402794

• Electro-thermal transport in silicon and carbon nanotube devices NONEQUILIBRIUM CARRIER DYNAMICS IN SEMICONDUCTORS PROCEEDINGS Pop, E., Mann, D., ROWLETTE, J., Goodson, K., Dai, H. 2006; 110: 195-199

  View details for Web of Science ID 000242486900044

• Multiphysics modeling and impact of thermal boundary resistance in phase change memory devices 2006 PROCEEDINGS 10TH INTERSOCIETY CONFERENCE ON THERMAL AND THERMOMECHANICAL PHENOMENA IN ELECTRONICS SYSTEMS, VOLS 1 AND 2 Reifenberg, J., Pop, E., Gibby, A., Wong, S., Goodson, K. 2006: 106-113

  View details for Web of Science ID 000243624500013

• Thermal properties of metal-coated vertically-aligned single wall nanotube films 2006 PROCEEDINGS 10TH INTERSOCIETY CONFERENCE ON THERMAL AND THERMOMECHANICAL PHENOMENA IN ELECTRONICS SYSTEMS, VOLS 1 AND 2 Panzer, M., Zhang, G., Mann, D., Hu, X., Pop, E., Dai, H., Goodson, K. E. 2006: 1306-1313

  View details for Web of Science ID 000243624500180

• Advanced cooling technologies for microprocessors Kenny, T. W., Goodson, K. E., Santiago, J. G., Wang, E., Koo, J., Jiang, L., Pop, E., Sinha, S., Zhang, L., Fogg, D., Yao, S., Flynn, R., Chang, C., Hidrovo, C. H. WORLD SCIENTIFIC PUBL CO PTE LTD. 2006: 301-313

  View details for Web of Science ID 000241022300016

• Negative differential conductance and hot phonons in suspended nanotube molecular wires PHYSICAL REVIEW LETTERS Pop, E., Mann, D., Cao, J., Wang, Q., Goodson, K. E., Dai, H. J. 2005; 95 (15)

  Abstract

  Freely suspended metallic single-walled carbon nanotubes (SWNTs) exhibit reduced current carrying ability compared to those lying on substrates, and striking negative differential conductance at low electric fields. Theoretical analysis reveals significant self-heating effects including electron scattering by hot nonequilibrium optical phonons. Electron transport characteristics under strong self-heating are exploited for the first time to probe the thermal conductivity of individual SWNTs (approximately 3600 W m-1 K-1 at T=300 K) up to approximately 700 K, and reveal a 1/T dependence expected for umklapp phonon scattering at high temperatures.

  View details for DOI 10.1103/PhysRevLett.95.155505

  View details for Web of Science ID 000232443400039

  View details for PubMedID 16241738

• Monte Carlo simulation of Joule heating in bulk and strained silicon APPLIED PHYSICS LETTERS Pop, E., DUTTON, R. W., Goodson, K. E. 2005; 86 (8)

  View details for DOI 10.1063/1.1870106

  View details for Web of Science ID 000227609000032

• Thermal phenomena in deeply scaled MOSFETs Rowlette, J., Pop, E., Sinha, S., Panzer, M., Goodson, K. IEEE. 2005: 1005-1008

  View details for Web of Science ID 000236225100230

• Joule heating under quasi-ballistic transport conditions in bulk and strained silicon devices SISPAD: 2005 INTERNATIONAL CONFERENCE ON SIMULATION OF SEMICONDUCTOR PROCESSES AND DEVICES Pop, E., Rowlette, J. A., DUTTON, R. W., Goodson, K. E. 2005: 307-310

  View details for Web of Science ID 000234260200076

• Electro-thermal transport in metallic single-wall carbon nanotubes for interconnect applications IEEE INTERNATIONAL ELECTRON DEVICES MEETING 2005, TECHNICAL DIGEST Pop, E., Mann, D., Reifenberg, J., Goodson, K., Dai, H. J. 2005: 261-264

  View details for Web of Science ID 000236225100058

• Thermal simulation techniques for nanoscale transistors Rowlette, J., Pop, E., Sinha, S., Panzer, M., Goodson, K. IEEE. 2005: 225-228

  View details for Web of Science ID 000234559700031

• Analytic band Monte Carlo model for electron transport in Si including acoustic and optical phonon dispersion JOURNAL OF APPLIED PHYSICS Pop, E., DUTTON, R. W., Goodson, K. E. 2004; 96 (9): 4998-5005

  View details for DOI 10.1063/1.1788838

  View details for Web of Science ID 000224799300042

• Electro-thermal comparison and performance optimization of thin-body SOI and GOI MOSFETs Pop, E., Chui, C. O., Sinha, S., Dutton, R., Goodson, K. IEEE. 2004: 411-414

  View details for Web of Science ID 000227158500093

• Thermal phenomena in nanoscale transistors ITHERM 2004, VOL 1 Pop, E., Goodson, K. E. 2004: 1-7

  View details for Web of Science ID 000222478500001

• Thermal analysis of ultra-thin body device scaling 2003 IEEE INTERNATIONAL ELECTRON DEVICES MEETING, TECHNICAL DIGEST Pop, E., Dutton, R., Goodson, K. 2003: 883-886

  View details for Web of Science ID 000189158800202

• Detailed heat generation simulations via the Monte Carlo method 2003 IEEE INTERNATIONAL CONFERENCE ON SIMULATION OF SEMICONDUCTOR PROCESSES AND DEVICES Pop, E., Dutton, R., Goodson, K. 2003: 121-124

  View details for Web of Science ID 000185660800030