Light-induced grating spectroscopy studies of hole transport in LaGaO3 crystals

The results of the absorption and photocurrent measurements and light-induc ed grating spectroscopy of undoped LaGaO3 crystals near room temperature ar e presented. Several absorption bands in the visible and near-ultraviolet r egion have been detected. Reversible photochromic effect has been observed in the nonoxidized crystals. The results of measurements show that the main absorption band in crystals annealed in air, peaked at 22 500 cm(-1), whic h also coincides with the main band in the photocurrent spectrum, is associ ated with the hole-related defect. The diffusion of holes is revealed in th e light-induced grating's experiments. The diffusion is thermally activated with an activation energy equal to 0.75 +/- 0.03 eV. This value of the act ivation energy of hole diffusion is responsible for large changes of the di ffusion coefficients, which increase more than two orders of magnitude betw een 20 degrees and 70 degrees C. [S0163-1829(99)00448-8].