Investigation Of Electric Field Threshold Of GaAs Photoconductive Semiconductor Switch Triggered By 1.6 ?J Laser Diode

Gallium arsenide photoconductive semiconductor switch(GaAs PCSS)has drawn a widely attention for the outstanding characteristics,such as the simple structure,fast response,low jitter,high withstand voltage and high current.However,the development of the high power application,such as,optically activated fire-sets and electro-optic modulators,requires it to be solid-state,compact and low-cost.This has motivated a significant amount of researches in the switch to use the compact light source(such as a LD)instead of the desktop laser for GaAs PCSS triggering.We built the pulsed LD systems and tested circuits for the research of electric field threshold on GaAs PCSS as the compact requirement on its development.The optical energy of the pulsed LD is proportional to the input voltage with a peak value of 1.6?J,while the main spectrum of the LD is 905nm.The time-domain spectroscopy of the optical pulse is with a rising time of 7.1ns and a pulse width of 25.7ns.This paper primarily investigates the effects of trigger position?spacing distance and the temperature to electric field threshold.The experiment proves that:(1)Along the x axis direction and making the trigger position shifting from the cathode to the anode,when the rectangular spot is perpendicular to two electrodes the electric field threshold increases linearly.And when the rectangular spot is parallel to the electrodes,the electric field threshold exhibits an asymmetric parabola-like curve.(2)Along the y axis direction and changing the distance between the LD head and the switch,when the rectangular spot is perpendicular to two electrodes the electric field threshold increases stair-likely.And when the rectangular spot is parallel to the electrodes,the electric field threshold exhibits an asymmetric parabola-like curve.(3)When the temperature increases,electric field threshold of nonlinear mode decreases whether the rectangular spot is perpendicular or parallel to the electrodes.Study the reason:(1)The operated distance of transferred-electron,growing distance of the photon-activated charge domain and the effective illuminated optical are different,so the electric field threshold presents different rules;(2)Space distance is different so that the initial co ncentration o f the photon-activated charges is different,which is important to the turn-on of nonlinear mode.(3)When the trigger position and the distance between the LD head and the switch are fixed,the number and the concentratio n of photo n-activated charge are fixed.In that case,the change of temperature leads to the change of intrinsic carrier concentration,and the electric field threshold decreases when the temperature increases.The result suggests a useful technique to effectively lower the threshold bias under these three different conditions.And the method is useful in effectively trigger GaAs PCS S under laser power of the order of ?J.