Ultrafast Optical-Pump Terahertz-Probe Spectroscopy of the Carrier Relaxation and Recombination Dynamics in Epitaxial Graphene
Ultrafast Optical-Pump Terahertz-Probe Spectroscopy of the Carrier Relaxation and Recombination Dynamics in Epitaxial Graphene
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DOI：
10.1021/nl8019399
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发表时间：
2008-12-01
期刊：
影响因子：
10.8
通讯作者：
Spencer, Michael G.
中科院分区：
文献类型：
--
作者：
George, Paul A.;Strait, Jared;Spencer, Michael G.
利用光泵太赫兹探测光谱研究了外延石墨烯中光生电子和空穴的超快弛豫和复合动力学。石墨烯在太赫兹频率下的电导率取决于载流子浓度以及载流子能量分布。因此，时间分辨的电导率的研究可以用来探测与载流子带内弛豫和带间复合相关的动力学。我们首次报道了外延石墨烯中的电子-空穴复合时间。我们的研究结果表明，载流子冷却发生在亚皮秒的时间尺度和带间复合时间的载流子密度依赖。
The ultrafast relaxation and recombination dynamics of photogenerated electrons and holes in epitaxial graphene are studied using optical-pump terahertz-probe spectroscopy. The conductivity in graphene at terahertz frequencies depends on the carrier concentration as well as the carrier distribution in energy. Time-resolved studies of the conductivity can therefore be used to probe the dynamics associated with carrier intraband relaxation and interband recombination. We report the electron-hole recombination times in epitaxial graphene for the first time. Our results show that carrier cooling occurs on subpicosecond time scales and that interband recombination times are carrier density dependent.