Experimental evidence of disorder enhanced electron-phonon scattering in graphene devices

Evangeli, Charalambos and McCann, Edward and Swett, Jacob L. and Tewari, Sumit and Bian, Xinya and Thomas, James and Briggs, G. Andrew D. and Kolosov, Oleg V. and Mol, Jan A. (2021) Experimental evidence of disorder enhanced electron-phonon scattering in graphene devices. Carbon, 178. pp. 632-639. ISSN 0008-6223

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Abstract

Induced disorder in graphene enables changes in the electrical and thermal transport. It has been shown previously that disorder is very important for electron cooling in graphene through disorder-assisted electron-phonon scattering, particularly via the supercollisions process. Here we study electron momentum relaxation due to electron-phonon scattering while increasing the degree of disorder. With in-situ Scanning Thermal Microscopy we monitor the temperature rise in the constriction of a bow tie-shaped graphene device while increasing the disorder by means of feedback-controlled voltage ramps at high-currents. Analysis of the combined thermal and electrical measurements shows that, the relative change of the momentum scattering rate vs temperature, as measured at room temperature, increases with strong local disorder. By excluding candidate mechanisms for this phenomenon, including a change of the charge density and activation of optical phonons, we conclude that the observed increase in the temperature dependent part of the scattering rate is likely due to new acoustic phonon scattering channels that open up as disorder increases.

Item Type:
Journal Article
Journal or Publication Title:
Carbon
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1600
Subjects:
ID Code:
150317
Deposited By:
Deposited On:
04 Jan 2021 10:35
Refereed?:
Yes
Published?:
Published
Last Modified:
16 Jun 2021 08:50