Effects of homojunction on the reflected and transmitted waves at the interface between two thermoelastic semiconductor half spaces

Abstract

It is systematically investigated that the influence of interface effect resulted from one homojunction on the reflected and transmitted thermoelastic waves between two bonded homogeneous isotropic thermoelastic semiconductor half spaces in this paper. Considering the geometrical and physical characteristics of homojunction, it is approximately treated as a two-dimensional isotropic imperfect interface without geometrical thickness mathematically but with elastic, thermal and semiconductor properties depicted through a dimensionless characteristic length factor physically. Considering the coupling effect of mechanical displacement, temperature change and charge carrier concentration perturbation, the imperfect interface boundary condition is established based on the generalized Green-Naghdi theory, the surface and interface elastic theory and the physical property of homojunction. The algebraic equation resulted from this imperfect interface boundary condition is solved to obtain the reflected and transmitted coefficients of thermoelastic waves expressed in the energy flux ratio, which are verified by the principle of energy conservation. The numerical calculation results demonstrate that the increase of geometrical thickness of homojunction and the angular frequency of thermoelastic waves can enhance the interface imperfect property and arise more evident influence of interface effect. Meanwhile, the interface effect has a more evident influence on the thermoelastic waves propagating along the interface normal direction. The physical mechanism revealed through the establishment of mathematical model provides a theoretical basis for using PN junction to regulate the propagation properties of thermoelastic waves in thermoelastic semiconductors.