Electron-phonon cooling in large monolayer graphene devices

We present thermal measurements of large area (over \(1,000\)~\(\mu\)m\(^2\)) monolayer graphene samples at cryogenic temperatures to study the electron-phonon thermal conductivity of graphene. By using two large samples with areas which differ by a factor of 10, we are able to clearly show the area...

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Bibliographic Details
Published in:arXiv.org 2015-05
Main Authors: McKitterick, Christopher B, Rooks, Michael J, Prober, Daniel E
Format: Article
Language:English
Subjects:
Cooling
Cryogenic temperature
Deformation mechanisms
Electrons
Graphene
Mathematical models
Monolayers
Phonons
Temperature dependence
Thermal conductivity
Thermal measurement
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Summary:We present thermal measurements of large area (over \(1,000\)~\(\mu\)m\(^2\)) monolayer graphene samples at cryogenic temperatures to study the electron-phonon thermal conductivity of graphene. By using two large samples with areas which differ by a factor of 10, we are able to clearly show the area dependence of the electron-phonon cooling. We find that, at temperatures far below the Bloch-Gruneisen temperature \(T_\mathrm{BG}\), the electron-phonon cooling power is accurately described by the \(T^4\) temperature dependence predicted for clean samples. Using this model, we are able to extract a value for the electron-phonon coupling constant as a function of gate voltage, and the graphene electron-lattice deformation potential. We also present results for thermal conductance at higher temperatures, above \(T_\mathrm{BG}/4\), for which the clean limit no longer applies. In this regime we find a cooling power which is accurately described qualitatively, but not quantitatively, by a model which predicts the emission of very high energy phonons through a disorder-assisted mechanism.
ISSN:2331-8422
DOI:10.48550/arxiv.1505.07034