Influence of gamma doses on the optical and electrical properties of oxygen-impurity and chromium-doped GaAs

A systematic investigation of the changes in the optical and electrical properties of GaAs(O):Cr under different γ-irradiation doses (0-500 kGy) is presented in this study. The Raman spectra of GaAs(O):Cr single crystal at wavelengths of 785 and 532 nm were analyzed after gamma irradiation. The appearance of the transverse-optical (TO) phonon mode and the blueshift of the TO peak reflect the presence of compressive stress and strain under irradiation. The Cr-As peak, observed in the Raman spectrum using a 532 nm excitation wavelength, shifted from 328.4 cm-1 to 326.3 cm-1, indicating a red shift. Fourier transform infrared (FTIR) spectroscopy revealed that under gamma irradiation, the broadening and shifting of the OAs and Ga-O-Ga peaks led to their merging in the infrared spectrum. In the 100-300 K range, with increasing irradiation dose, the charge carrier mobility increased, while the charge carrier concentration decreased, and their corresponding values were presented.