Temperature-dependent delay time in GaAs high-power high-speed photoconductive switching devices

Temperature-dependent delay time between the beginning of optical illumination and the onset of switching in the transient response of semi-insulating GaAs high-power, high-speed photoconductive switching devices is studied in this letter. The temperature-dependent electroabsorption caused by absorption edge shifting due to bandgap narrowing is found to be responsible for the experimentally observed temperature-dependence in delay time. Our analysis shows delay time has little dependence on temperature when photon energy is larger than band gap, but depends strongly on temperature when photon energy is smaller than band gap and the applied electric field is low.<>