Light-induced grating spectroscopy studies of hole transport inLaGaO3crystals

The results of the absorption and photocurrent measurements and light-induced grating spectroscopy of undoped LaGaO3 crystals near room temperature are presented. Several absorption bands in the visible and near-ultraviolet region 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, which also coincides with the main band in the photocurrent spectrum, is associated with the hole-related defect. The diffusion of holes is revealed in the light-induced grating’s experiments. The diffusion is thermally activated with an activation energy equal to 0.7560.03 eV. This value of the activation energy of hole diffusion is responsible for large changes of the diffusion coefficients, which increase more than two orders of magnitude between 20° and 70 °C. @S0163-1829~99!00448-8#