Near-Infrared Photoluminescence in the Femtosecond Time Region in Monolayer Graphene on SiO2

详细信息    查看全文

• 作者：Takeshi Koyama ; Yoshito Ito ; Kazuma Yoshida ; Masaharu Tsuji ; Hiroki Ago ; Hideo Kishida ; Arao Nakamura
• 刊名：ACS Nano
• 出版年：2013
• 出版时间：March 26, 2013
• 年：2013
• 卷：7
• 期：3
• 页码：2335-2343
• 全文大小：417K
• 年卷期：v.7,no.3(March 26, 2013)
• ISSN：1936-086X

文摘

We investigate the dynamical properties of photoexcited carriers in a single monolayer of graphene at room temperature in air using femtosecond time-resolved luminescence spectroscopy. The luminescence kinetics are observed in the near-infrared region of 0.7鈥?.4 eV and analyzed based on the two-temperature model describing the cooling of thermalized carriers via the carrier鈥搊ptical phonon interaction. The observed luminescence in the range 0.7鈥?.9 eV is well reproduced by the model. In the range 1.0鈥?.4 eV, however, the luminescence, which decays in 300 fs, cannot be reproduced by this model. These results indicate that the carrier system is not completely thermalized in 300 fs. We also show the importance of the carrier-doping effect induced by the substrate and surrounding environment in the carrier cooling dynamics and the predominance of optical phonons over acoustic phonons in the carrier鈥損honon interactions even at a temperature of 400 K.

Keywords:

monolayer graphene; photocarrier relaxation; carrier cooling dynamics; carrier鈭抪honon interaction; photoluminescence; femtosecond time-resolved luminescence spectroscopy