Diversity of ultrafast hot-carrier-induced dynamics and striking sub-femtosecond hot-carrier scattering times in graphene

被引：17

作者：

Chen, Ke ^{[1
]}

Li, Huihui ^{[1
]}

Ma, Lai-Peng ^{[2
]}

Ren, Wencai ^{[2
]}

Chung, Ting-Fung ^{[3
]}

Cheng, Hui-Ming ^{[2
]}

Chen, Yong P. ^{[3
]}

Lai, Tianshu ^{[1
]}

机构：

[1] Sun Yat Sen Univ, Sch Phys & Engn, State Key Lab Optoelect Mat & Technol, Guangzhou 510275, Guangdong, Peoples R China

[2] Chinese Acad Sci, Inst Met Res, Shenyang Natl Lab Mat Sci, Shenyang 110016, Peoples R China

[3] Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA

来源：

CARBON | 2014年 / 72卷

基金：

中国国家自然科学基金;

关键词：

RELAXATION;

D O I：

10.1016/j.carbon.2014.02.039

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

We study ultrafast dynamics in graphene grown by chemical vapor deposition, which presents a positive peak followed by a negative slow recovery process, and is different from the fully positive or negative dynamics reported. We discuss the diversity of ultrafast dynamics. A dynamic model of differential optical conductivity is developed to simulate ultrafast dynamics. It is found that the diversity of ultrafast dynamics originates from multiple parameter dependence. The appearance of ultrafast dynamics is mainly determined by the position of probed level with respect to static Fermi energy and/or momentum scattering time. The dynamic model is used to best fit the observed ultrafast dynamics to retrieve dynamic time constants. The thermalizing and cooling times of optical phonons are found consistent with the reported values, but a striking sub-femtosecond momentum scattering time and a sub-picosecond time of electron-hole recombination are obtained. The sub-femtosecond scattering time is much shorter than several to a few hundred femtoseconds accepted currently. (C) 2014 Elsevier Ltd. All rights reserved.

引用

页码：402 / 409

页数：8