Photoacoustic investigation of the carrier transport processes and the thermal properties in n-type GaAs

The carrier-transport processes and the thermal properties of n-type GaAs were investigated by using photoacoustic spectroscopy. The frequency dependence of the photoacoustic signal showed that the photoacoustic effects in n-type GaAs were associated with instantaneous thermalization, nonradiative bulk recombination, and nonradiative surface recombination. In particular, it was found that in the high-frequency region the heat was primarily generated by the nonradiative bulk recombination and the nonradiative surface recombination processes. For the low-frequency region, however, the instantaneous thermalization process was the main origin of the heat. A thermal diffusivity of 0.51 cm ²/s, a diffusion coefficient of 5.2 cm ²/s, a surface recombination velocity of 355 cm/s, and a relaxation time of 5.8 μs were also obtained from the curve fitting of the photoacoustic phase spectrum.