Transient surface photoconductivity of GaAs emitter studied by terahertz pump-emission spectroscopy  

作　　者：施宇蕾 周庆莉 张存林 

机构地区：[1]Beijing Key Laboratory for Terahertz Spectroscopy and Imaging, Key Laboratory of Terahertz Optoelectronics, Ministry of Education, Department of Physics, Capital Normal University

出　　处：《Chinese Physics B》2009年第10期4515-4520,共6页中国物理B（英文版）

基　　金：Project supported by the National Basic Research Program (973 Program) (Grant Nos 2007CB310408 and 2006CB302901);the National Natural Science Foundation of China (Grant No 10804077);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, Chinese Academy of Sciencs

摘　　要：This paper investigates the ultrafast carrier dynamics and surface photoconductivity of unbiased semi-insulating GaAs in detail by using a terahertz pump-emission technique. Based on theoretical modelling, it finds that transient photoconductivity plays a very important role in the temporal waveform of terahertz radiation pulse. Anomalous enhancement in both terahertz radiation and transient photoconductivity is observed after the excitation of pump pulse and we attribute these phenomena to carrier capture in the EL2 centers. Moreover, the pump power- and temperature- dependent measurements are also performed to verify this trapping model.This paper investigates the ultrafast carrier dynamics and surface photoconductivity of unbiased semi-insulating GaAs in detail by using a terahertz pump-emission technique. Based on theoretical modelling, it finds that transient photoconductivity plays a very important role in the temporal waveform of terahertz radiation pulse. Anomalous enhancement in both terahertz radiation and transient photoconductivity is observed after the excitation of pump pulse and we attribute these phenomena to carrier capture in the EL2 centers. Moreover, the pump power- and temperature- dependent measurements are also performed to verify this trapping model.

关 键 词：TERAHERTZ ultrafast carrier trapping surface photoconductivity 

分 类 号：O472.8[理学—半导体物理]