Photoacoustic effect in semiconductors: Influence of field temperature on carrier diffusion and recombination

Abstract

A quantitative derivation is presented for the heat transport in bipolar semiconductors taking into account the generation and heating of carriers on the surface of the sample due to an incident modulated laser beam, finite carrier diffusion, and recombination in the solid. The temperature distribution is calculated using appropriate boundary conditions according to the photoacoustic experimental conditions. In addition, special emphasis is made on the heat power density generated in the sample due to the recombination of the electron–hole pair and the effect of the inhomogeneous temperature distribution on the thermal generation rate of carriers in the photoacoustic signal. Finally, the effect of two temperatures associated with the quasiparticle (electrons and phonons) systems is considered in the finite electron–phonon energy interaction in the solid.