High Gain Lateral Semi-Insulating GaAsPhotoconductive Switch Triggered by 1064 nm Laser Pulses

Abstract

We report on the experimental results of a lateralsemi-insulating GaAs photoconductive switch, with a gap of 8 mm between twoelectrodes, triggered by 1064 nm laser pulses at a wavelength beyond theGaAs absorption edge. Both the linear and nonlinear modes of the switch wereobserved when it was triggered by light pulses with an energy of 1.9 mJ and apulse width of 60 ns, and operated at high voltages of 3 and 5 kV. Theresults show that when the semi-insulating GaAs photoconductive switchoperates under an electrical field of 4.37 kV/cm, it will enter into thelinear mode first, and then the switch will undergo the nonlinear mode(lock-on) after a delay of about 20-100 ns. It is worth noticing that thedelay time under high light energy is longer than that in the low opticalenergy. The non-intrinsic absorption mechanism is discussed. EL2 deep leveldefects and double-photon absorption in GaAs may play a key part inthe absorption process.