BIREFRINGENCE OF CADMIUM TELLURIDE AT 77 K INDUCED BY UNIAXIAL-STRESS

The spectral dependences of the piezobirefringence in CdTe is determin ed for different crystallographic directions of uniaxial compression a t T=77 K-the temperature at which the photosensitive heterostructures CdxHg1-xTe/CdTe are actually used. The dispersion of the piezobirefrin gence near the fundamental absorption edge at T=77 K is stronger than at room temperature, and the piezobirefringence itself reaches a much higher value. Near the fundamental absorption edge the phase differenc e between the radiation components for polarization parallel and perpe ndicular to the compression axis is a nonlinear function of the strain . The dispersion of the piezobirefringence is analyzed theoretically i n the four-band Kane model, taking into account the explicit form of t he band spectrum and the wave functions of electrons and holes. The te mperature dependence of the dispersion of the piezobirefringence is ex plained. (C) 1996 American Institute of Physics.