摘要
Femtosecond pump-terahertz probe studies of carrier dynamics in semi-insulating CaAs have been investigated in detail for various pump powers. It is observed that, at high pump powers, the reflection peaks flip to the opposite polarity and dramatically enhance as the pump arrival time approaches the reflected wave of the terahertz pulse. The abnormal polarity-flip and enhancement can be interpreted by the pump-induced enhancement in the photoconductivity of GaAs and half-wave loss. Moreover, the carrier relaxation processes and surface states filling in GaAs are also studied in these measurements.
Femtosecond pump-terahertz probe studies of carrier dynamics in semi-insulating CaAs have been investigated in detail for various pump powers. It is observed that, at high pump powers, the reflection peaks flip to the opposite polarity and dramatically enhance as the pump arrival time approaches the reflected wave of the terahertz pulse. The abnormal polarity-flip and enhancement can be interpreted by the pump-induced enhancement in the photoconductivity of GaAs and half-wave loss. Moreover, the carrier relaxation processes and surface states filling in GaAs are also studied in these measurements.
基金
Project supported by the National Basic Research Program of China (973 Program) (Grant Nos 2007CB310408 and2006CB302901)
the National Natural Science Foundation of China (Grant No 10804077)
Science Foundation of Beijing Municipal Commission of Education (Grant No KM200910028006)
Funding Project for Academic Human Resources Development in Institutions of Higher Learning under the Jurisdiction of Beijing Municipality
supported by State Key Laboratory of Functional Materials for Informatics,Shanghai Institute of Microsystem and Information Technology,the Chinese Academy of Sciences
