The Characteristic Of Photoconductive Semiconductor Switch Triggered By The Laser Diode

Photoconductive Semiconductor Switch (PCSS) is an all solid-state semiconductor switch which is triggered by laser pulse. PCSS has a wide prospect of application in the field of pulsed power technology, terahertz field and super-speed electronics, etc., for PCSS provides many advantages such as fast response speed, high repetition rate, low trigger jitter, photoelectric isolate, easy integration, (and) compact size and so on. The characteristic of GaAs PCSS triggered by the laser diode is researched in this paper, and the turn-on process of PCSS which is worked under low trigger energy and low bias voltage is analyzed. The linear-alike model of PCSS is presented, and we believe it will be helpful for the non-linear mode research.The material characteristics of GaAs PCSS are introduced at the beginning of this paper, and the changing process of carriers is discussed when the switch is triggered on a big bias voltage. Based on these, the characteristic of PCSS triggered by the laser diode is researched, and the theoretical model which has already been put forward is corrected by theoretical analysis. The modified model explains the experimental phenomena very well. The experimental results show that the big(bigger) the bias voltage and conducted current are, the higher the conversion efficiency is. The best trigger position of PCSS is cathode. In addition, this paper also explains the reason why we cannot observe the lock-on effect when transmission line is used to store energy is that the capacity of the transmission line is too small. But we can control the switch turn-off by utilizing the transfer characteristic of the transmission line.This paper first proposed the linear-alike theoretical model by researching the PCSS which is worked in low bias voltage and low trigger energy. The experiment is designed to verify the accuracy of the model. The linear-alike output has a great influence on the output performance of the non-linear mode. The experimental results show that delay and jitter of non-linear mode are mainly caused by the linear-alike output. Based on this, a trigger method used to shorten delay and reduce jitter is presented. Furthermore, combining the linear-alike model and experimental results, we put forward a method to calculate the ionization rate in a specific voltage. Calculations show that the ionization rate of GaAs PCSS used in the experiment is 0.214 cm-1 when the switch works under 10kV bias voltage.