Nanoscale Joule heating, Peltier cooling and current crowding at graphene–metal contacts

Grosse, Kyle L.; Bae, Myung‐Ho; Lian, Feifei; Pop, Eric; King, William P.

doi:10.1038/nnano.2011.39

Cited by 296 publications

(268 citation statements)

References 29 publications

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“…Consequently, in the case of suspended nanowires the ( , ) reflects the temperature of the nanowires as well as the background temperature of the substrate in-between the wires. In contrast, contact-based vacuum SThM [11][12][13][14][15] would detect only the temperature of the suspended nanowires if scanning at a height corresponding to the top surface plane of the nanowires.…”

Section: S4 Experimental Demonstration Of the Tsot Spatial Resolutionmentioning

confidence: 97%

Nanoscale thermal imaging of dissipation in quantum systems

Halbertal

Cuppens

Shalom

et al. 2016

Nature

197

175

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Energy dissipation is a fundamental process governing the dynamics of physical, chemical, and biological systems. It is also one of the main characteristics distinguishing quantum and classical phenomena. In condensed matter physics, in particular, scattering mechanisms, loss of quantum information, or breakdown of topological protection are deeply rooted in the intricate details of how and where the dissipation occurs. Despite its vital importance the microscopic behavior of a system is usually not formulated in terms of dissipation because the latter is not a readily measureable quantity on the microscale. Although nanoscale thermometry is gaining much recent interest [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] , the existing thermal imaging methods lack the necessary sensitivity and are unsuitable for low temperature operation required for study of quantum systems. Here we report a superconducting quantum interference nano-thermometer device with sub 50 nm diameter that resides at the apex of a sharp pipette and provides scanning cryogenic thermal sensing with four orders of magnitude improved thermal sensitivity of below 1 µK/Hz 1/2 . The non-contact non-invasive thermometry allows thermal imaging of very low nanoscale energy dissipation down to the fundamental Landauer limit [16][17][18] of 40 fW for continuous readout of a single qubit at 1 GHz at 4.2 K. These advances enable observation of dissipation due to single electron charging of individual quantum dots in carbon nanotubes and reveal a novel dissipation mechanism due to resonant localized states in hBN encapsulated graphene, opening the door to direct imaging of nanoscale dissipation processes in quantum matter. 2 Investigation of energy dissipation on the nanoscale is of major fundamental interest for a wide range of disciplines from biological processes, through chemical reactions, to energy-efficient computing [1][2][3][4][5] . Study of dissipation mechanisms in quantum systems is of particular importance because dissipation demolishes quantum information. In order to preserve a quantum state the dissipation has to be extremely weak and hence hard to measure. As a figure of merit for detection of low power dissipation in quantum systems 16 we consider an ideal qubit operating at a typical readout frequency of 1 GHz. Landauer's principle states the lowest bound on energy dissipation in an irreversible qubit operation to be 0 = B ln 2, where B is Boltzmann's constant and is the temperature 17,18 . At = 4.2 K, 0 = 410 -23 J, several orders of magnitude below 10 -19 J of dissipation per logical operation in present day superconducting electronics and 10 -15 J in CMOS devices 19,20 . Hence the power dissipated by an ideal qubit operating at a readout rate of = 1 GHz will be as low as = 0 = 40.2 fW. The resulting temperature increase of the qubit will depend on its size and the thermal properties of the substrate. For example, a 120 × 120 nm 2 device on a 1 µm thick SiO 2 /Si substrate dissipating 40 fW will heat up by about 3 µK (Fig. 1). Suc...

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Section: S4 Experimental Demonstration Of the Tsot Spatial Resolutionmentioning

confidence: 97%

Nanoscale thermal imaging of dissipation in quantum systems

Halbertal

Cuppens

Shalom

et al. 2016

Nature

197

175

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“…The R C dependence on temperature and carrier density is given through its dependence on sheet resistance R S (see Supplement Section C); thus, R C for such GNRs is almost independent of temperature like the mobility, but it scales approximately as the inverse square root of carrier density, ∝ (n + p) -1/2 (also see refs. 27,36). The uncertainty in the R C extraction arises partly from the fitting algorithm (as for mobility) and partly from uncertainty of the GNR width which fans out under the metal contact, taken here between W and W + 2L T where L T is the current transfer length into the contact electrode 36 .…”

Section: Previous Studies Have Characterized Individualmentioning

confidence: 99%

Transport in Nanoribbon Interconnects Obtained from Graphene Grown by Chemical Vapor Deposition

et al. 2012

Self Cite

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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.

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“…The images reveal pitting of the metal at the contact resulting in reduced contact area between the nanowire and electrode. The pitting may be due to current crowding at the leading edge of the metal-nanowire contact region [41]. The localized region of high current density at the leading edge may exacerbate electromigration of the metal electrode.…”

Section: Electrothermal Analysis Of Zinc Oxide Nanowiresmentioning

confidence: 99%

Electrothermal phenomena in zinc oxide nanowires and contacts

LeBlanc

Phadke

Kodama

et al. 2012

Applied Physics Letters

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Heat generation along nanowires and near their electrical contacts influences the feasibility of energy conversion devices. This work presents ZnO nanowire electrical resistivity data and models electrothermal transport accounting for heat generation at metal-semiconductor contacts, axial thermal conduction, and substrate heat losses. The current-voltage relationships and electron microscopy indicate sample degradation is caused by the interplay of heat generation at contacts and within the nanowire volume. The model is used to interpret literature data for Si, GaN, and ZnO nanowires. This work assists with electrothermal nanowire measurements and highlights practical implications of utilizing solution-synthesized nanowires. The work was conducted at Stanford University from 2010

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Nanoscale Joule heating, Peltier cooling and current crowding at graphene–metal contacts

Cited by 296 publications

References 29 publications

Nanoscale thermal imaging of dissipation in quantum systems

Nanoscale thermal imaging of dissipation in quantum systems

Transport in Nanoribbon Interconnects Obtained from Graphene Grown by Chemical Vapor Deposition

Electrothermal phenomena in zinc oxide nanowires and contacts

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