Abstract
In view of the potential effects of As-precipitates on electrical and optical properties of GaAs:As, furnace-annealed GaAs:As as ultrafast photoconductors was studied. Femtosecond time-resolved reflectivity measurements revealed photoexcited carrier lifetimes of 0.3 ps and 1.8 ps for as-implanted and furnace-annealed GaAs:As materials respectively. The switching responses of the photoconductive switch (PCS) were examined by an external electro-optic sampling (EEOS) system. The dark currents of similar PCSs fabricated on the rapidly thermal annealed GaAs:As and semi-insulating GaAs were compared. Furnace-annealed GaAs:As PCS was found to be an excellent candidate for high-speed and high-field switch.