设计了横向结构的半绝缘GaAs光导开关,开关由600 μm厚的半绝缘GaAs晶片制成,电极间隙为20 mm。在不同的直流偏置电压下,使用波长为1 064 nm、能量为9.9 mJ的激光脉冲触发使开关导通,开关置于0.2 MPa的SF6气体环境中。在施加直流50 kV电压的情况下,使用Rogowski线圈测得开关的最大导通电流为1.1 kA。对实验结果进行分析表明:随着初始偏置电压的升高,回路流过的电荷与电容初始储存的电荷的比值不断提高,但都没有达到100%,即非线性模式下光导开关的关断原因并不是由于外电路的能量已经耗尽。对非本征光电导的情况,计算出开关的通态电阻为2.71 Ω。

A photoconductive semiconductor switch(PCSS) with a gap of 20 mm was fabricated from semi-insulating GaAs.Triggered by a laser pulse with an incident optical energy of 9.9 mJ and a wavelength of 1 064 nm,photoconductivity tests of the PCSS were performed at different bias voltages.The peak photocurrent through the switch in pressurized SF6 at 0.2 MPa was 11 kA at a bias voltage of 50 kV.The analyses suggest that the closure of GaAs PCSS operating in nonlinear mode is not always due to the fact that the energy has been dumped from the charging system by comparing the charge initially stored in the capacitors and the charge through the switch.The on-state resistance of the switch employing extrinsic photoconductivity is calculated to be 2.71 Ω.