GaBiAs: A material for optoelectronic terahertz devices

GaBiAs layers have been grown by molecular beam epitaxy at low (270-330 degrees C) temperatures and were characterized by several experimental techniques. It was shown that the spectral photosensitivity cutoff wavelength reaches similar to 1.4 mu m when the growth temperature is as low as 280 degrees C. Optical pump-terahertz probe measurements made on these layers have evidenced that the electron trapping time decreases with decreasing growth temperature from 20 to about 1 ps. GaBiAs layers were used for manufacturing photoconductive terahertz emitters and detectors, which, when excited with Ti:sapphire laser pulses, have demonstrated a signal bandwidth of 3 THz. (c) 2006 American Institute of Physics.