Hot Carrier Transport and Photocurrent Response in Graphene
Hot Carrier Transport and Photocurrent Response in Graphene
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DOI：
10.1021/nl202318u
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发表时间：
2011-11-01
期刊：
影响因子：
10.8
通讯作者：
Levitov, Leonid S.
中科院分区：
文献类型：
--
作者：
Song, Justin C. W.;Rudner, Mark S.;Levitov, Leonid S.
石墨烯中的强电子-电子相互作用有望通过吸收单个光子产生多重激发。我们表明，载流子倍增对光电流响应的影响通过非常低效的电子冷却而增强，导致大量的热载流子。热载流子介导的能量输运主导着光响应，并表现为量子效率可以超过1，以及光电流对栅电压的特征依赖。多重光电流标志的模式随栅极电压的变化而变化，提供了热载流子主导的输运和载流子倍增的指纹。
Strong electron electron interactions in graphene are expected to result in multiple-excitation generation by the absorption of a single photon. We show that the impact of carrier multiplication on photocurrent response is enhanced by very inefficient electron cooling, resulting in an abundance of hot carriers. The hot-carrier-mediated energy transport dominates the photoresponse and manifests itself in quantum efficiencies that can exceed unity, as well as in a characteristic dependence of the photocurrent on gate voltages. The pattern of multiple photocurrent sign changes as a function of gate voltage provides a fingerprint of hot-carrier-dominated transport and carrier multiplication.