Experimental evidence of disorder enhanced electron-phonon scattering in graphene devices
Experimental evidence of disorder enhanced electron-phonon scattering in graphene devices
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DOI：
10.1016/j.carbon.2020.12.012
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发表时间：
2021-04-03
期刊：
影响因子：
10.9
通讯作者：
Mol, Jan A.
中科院分区：
文献类型：
--
作者：
Evangeli, Charalambos;McCann, Edward;Mol, Jan A.
石墨烯中的诱导无序能够改变电和热传输。先前已经表明，通过无序辅助的电子-声子散射，特别是通过超碰撞过程，无序对于石墨烯中的电子冷却非常重要。在这里，我们研究电子动量弛豫由于电子-声子散射，同时增加无序度。与原位扫描热显微镜，我们监测的温度上升的蝴蝶结形的石墨烯器件的收缩区域，同时增加的障碍，通过反馈控制的电压斜坡在高电流密度。在低偏置制度相结合的热和电测量的分析表明，在室温下测量的动量散射率与温度的相对变化，增加与强的局部无序。通过排除这种现象的其他候选机制，包括电荷载流子密度的变化和光学声子的激活，我们得出结论，我们观察到的散射率的温度依赖性分量的增加可能是由于新的声学声子散射通道，随着无序度的增加而打开。(C)2020爱思唯尔有限公司保留所有权利。
Induced disorder in graphene enables changes in 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 region of a bowtie-shaped graphene device while increasing the disorder by means of feedback-controlled voltage ramps at high-current densities. Analysis of the combined thermal and electrical measurements in the low bias regime shows that the relative change of the momentum scattering rate vs temperature, as measured at room temperature, increases with strong local disorder. By excluding other candidate mechanisms for this phenomenon, including a change of the charge carriers density and activation of optical phonons, we conclude that the increase we observe in the temperature-dependent component of the scattering rate is likely due to new acoustic phonon scattering channels that open up as disorder increases. (C) 2020 Elsevier Ltd. All rights reserved.