Acceleration of Photocarrier Relaxation in Graphene Achieved by Epitaxial Growth: Ultrafast Photoluminescence Decay of Monolayer Graphene on SiC
Acceleration of Photocarrier Relaxation in Graphene Achieved by Epitaxial Growth: Ultrafast Photoluminescence Decay of Monolayer Graphene on SiC
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DOI：
10.1021/acs.jpcc.8b06845
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发表时间：
2018-08-23
影响因子：
3.7
通讯作者：
Kusunoki, Michiko
中科院分区：
文献类型：
--
作者：
Imaeda, Hirotaka;Koyama, Takeshi;Kusunoki, Michiko
石墨烯中光生载流子弛豫的加速导致其用于基于石墨烯的超快光学器件的性能的增强。可以通过利用石墨烯外部的弛豫路径来实现加速，以避免石墨烯中用于光生载流子弛豫的瓶颈。在这项研究中，我们研究了在室温下，通过时间分辨光致发光光谱的缓冲层在SiC上的外延和转移单层石墨烯的光载流子弛豫。在0.7 eV处，外延单层石墨烯中的光致发光衰减比转移单层石墨烯中的光致发光衰减快。通过三温模型计算发现，外延单层石墨烯的载流子-声子相互作用强度是转移单层石墨烯的3倍.这项研究表明，超快的光生载流子弛豫可以实现在石墨烯的外延生长。
Acceleration of photocarrier relaxation in graphene results in the enhancement of its properties for graphene-based ultrafast optical devices. The acceleration can be achieved by utilizing the relaxation paths outside the graphene to avoid bottlenecks in the graphene for photocarrier relaxation. In this study, we investigate photocarrier relaxation in epitaxial and transferred monolayer graphene on SiC with a buffer layer at room temperature by means of time-resolved photoluminescence spectroscopy. The photoluminescence decay at 0.7 eV in the epitaxial monolayer graphene is faster than that in the transferred monolayer graphene. On the basis of the three-temperature model calculation, it is found that the carrier-phonon interaction with phonons of the buffer layer for the epitaxial monolayer graphene is 3 times stronger than that for the transferred monolayer graphene. This study demonstrates that ultrafast photocarrier relaxation can be achieved in graphene by epitaxial growth.