Suppression of supercollision carrier cooling in high mobility graphene on SiC(0001)
Suppression of supercollision carrier cooling in high mobility graphene on SiC(0001)
复制标题
SiC(0001)上高迁移率石墨烯中超碰撞载流子冷却的抑制
DOI：
10.1103/physrevb.95.165303
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发表时间：
2017
影响因子：
3.7
通讯作者：
Shik Shi
中科院分区：
文献类型：
--
作者：
Takashi Someya;Hirokazu Fukidome;Hiroshi Watanabe;Takashi Yamamoto;Masaru Okada;Hakuto Suzuki;Yu Ogawa;Takushi Iimori;Nobuhisa Ishii;Teruto Kanai;Keiichiro Tashima;Baojie Feng;Susumu Yamamoto;Jiro Itatani;Fumio Komori;Kozo Okazaki;Shik Shi
石墨烯是一种含有无质量狄拉克费米子气体的二维碳晶体，有望成为一种可用于光子和光电器件的材料。全面了解光激发石墨烯中的载流子冷却对于它们的应用是必要的，然而，由于竞争冷却过程，电子-声子散射和超碰撞，使问题复杂化。具体而言，在能量收集中，超碰撞促进了载流子的进一步冷却，因此导致效率降低，从而对器件应用的可行性产生了怀疑。在这里，我们通过直接观察光激发载流子和数值分析一个唯象的双温模型，提出了在assubstrate上的三层石墨烯中抑制超碰撞的证据。知道超级碰撞限制了石墨烯基器件的能力，我们的研究结果为提高其性能提供了突破。
Graphene, a two-dimensional carbon crystal with a gas of massless Dirac fermions, has promise as a material that is useful in photonic and optoelectronic devices. A comprehensive understanding of carrier cooling in photoexcited graphene is necessary for their applications, however, as competing cooling processes, electron-phonon scattering, and supercollisions, complicate the problem. Specifically, in energy harvesting, supercollision promotes further carrier cooling and, therefore, leads to lower efficiency, placing doubt on the feasibility of device applications. Here we present evidence of suppressed supercollisions in trilayer graphene on asubstrate by directly observing photoexcited carriers and numerically analyzing a phenomenological two-temperature model. Knowing that supercollisions restrict the capabilities of graphene-based devices, our results provide a breakthrough for improving their performance.