Photothermal and photoacoustic effects in semiconductors and semiconductor structures

Abstract

A theory of photothermal and photoacoustic effects is developed, on which the contactless diagnostics of semiconductors and semiconductor structures are based. Photothermal and photoacoustic effects are characterized quantitatively by the variable temperature of the specimen surface being exposed and by its shift. These quantities are computed in this paper for a homogeneous semiconductor and a semiconductor with a p-n junction with electron transfer processes, heat liberation as a result of thermalization and charge carrier recombination and their passage through the potential barrier as well as nonthermal deformation mechanisms due to nonequilibrium carrier interaction with the lattice in terms of the deformation potential and the reverse piezoeffect taken into account. It is shown that the surface temperature and shift (particularly the phase of these responses) carry information about such semiconductor characteristics as the charge carrier lifetime, the surface recombination rate, the deformation potential constants, the depth of p-n junction location, the height of its potential barrier, etc.