Studies of Photon Energy Dependence of Transient Photocurrent in Semi-Insulating GaAs Materials by means of Photo-Deep-Level Fourier Spectroseopy and Photosensitivity Transient Spectroscopy

The photon energy dependence of the transient photocurrent in Cr-doped semi-insulating GaAs materials was investigated by photo-deep-level Fourier spectroscopy (photo-DLFS) and photosensitivity transient spectroscopy (PSTS). From the experimental results, it was found that photo-DLFS signals change systematically according to the change in the photon energy of monochromatic light; fourteen deep levels were detected. It is shown that measurements taken while continuously varying the photon energy are very useful in studying specified deep levels in cases where the signals of two or more deep levels overlap and in detecting the many deep levels by increasing the change in the occupancy probability at each deep level. Also, a photoquenching effect is shown to occur within the new photon energy range, 0.85-0.92 eV, by PSTS.