Study On High Field Transporation Characteristics Of GaAs Photoconductive Switches

GaAs photoconductive semiconductor switches (PCSS's), well known for their excellent characteristics, have a very broad prospect of applications in numerous fields such as the generation of high power ultra-wideband pulse and ultra-fast electronics. Especially, the PCSS's are paid much more attention to because they can operate in a nonlinear mode when the thresholds of activating optical energy and bias field. In view of the great prospect of PCSS's, this thesis studies the theoretical in nonlinear mode and the output voltage in linear mode PCSS.The main contributions in this thesis are as followings:A theoretical model of PCSS has been established based on drift diffusion theory. The absorption coefficient is expressed as the function of electric field. The stable state results in PCSS and the electric field distribution in PCSS after laser triggering are obtained by using finite difference method and computer simulation. The results are also analyzed. The electric field distribution in the stable state in PCSS is symmetrical. After the laser triggering, the electric field distribution become asymmetrical gradually. It become bigger in the anode, but become smaller in cathode. The output voltage in linear mode PCSS is analyzed. The factors which affect the output voltage such as the biased voltage, optical pulse energy, absorption coefficient, the gap length on the device and the chip materials are discussed.