半绝缘GaAs光电导开关体内热电子的光电导振荡特性  

Characteristics of photoconductivity oscillation in semi-insulating GaAs photoconductive semiconductor switches

作　　者：施卫[1] 薛红[1,2] 马湘蓉[1] 

机构地区：[1]西安理工大学应用物理系,西安710048 [2]渭南师范学院物理与电子工程系,渭南714000

出　　处：《物理学报》2009年第12期8554-8559,共6页Acta Physica Sinica

基　　金：国家重点基础研究发展计划(批准号:2007CB310406);国家自然科学基金(批准号:50837005;10876026);陕西省教育厅专项科研基金(批准号:09JK431);渭南师范学院科研基金(批准号:08YKF022;09YKZ021)资助的课题~~

摘　　要：用波长为532nm、脉冲宽度为5ns的超短激光脉冲触发电极间隙为4mm的半绝缘GaAs光电导开关,开关偏置电压从500V开始以步长50V逐渐增加,直到开关出现非线性电脉冲输出.研究表明,线性和非线性电脉冲波形均呈现出在经历一个主脉冲之后,其后跟随几个幅值较小且具有周期性和不同程度的减幅振荡.分析了开关体内载流子(热电子)的微观状态和输运过程,在直流偏置电场作用下,开关体内的热电子在电子-电子、电子-声子相互作用过程中,当它们的弛豫时间大于载流子的寿命时,光电子的输运可通过迁移率变化引起光电导振荡,这是开关输出电脉冲出现振荡的原因.The 4 mm gap and 5 ns pulse width semi-insulating GaAs photoconductive switches were triggered by 532 nm laser pulse with gradual increase of bias voltage from 500 V in steps of 50 V until the emergence of nonlinear electrical pulse. The expermental results showed that the linear and nonlinear electrical pulse waveforms had smaller amplitude and varying degrees of oscillation reduction after going through a main pulse. Then the microscopic state and transport process of carriers（hot-electron） in the switch material were studied in detail using the quantum theory. It was found that in the DC bias electric field,when the relaxation time of the hot-electrons in the electron-electron and electron-phonon interaction process is longer than the carrier life,the photoconductivity oscillation can be caused by the change of mobility in the process of optoelectronic transport,which is the main cause for the output electrical pulse to show oscillations.

关 键 词：光电导开关 热电子 弛豫 光电导振荡 

分 类 号：TN25[电子电信—物理电子学]