Effect of excitation intensity and electric field on the photoconductivity relaxation in CdxHg1−xTe/GaAs polycrystalline layers

The photoconductivity relaxation and the stationary photoconductivity in the n-Cd0.8Hg0.2Te compensated polycrystalline layers at T=300 K have been investigated as a function of the light intensity and the strength of applied electric field E. It is demonstrated that, at low excitation intensities, the saturation of stationary photoconductivity and a decrease in the relaxation time with an increase in E are caused by the minority carrier extraction. The effect of minority carrier extraction is analyzed with due regard for the internal electric field of potential barriers in intergranular layers. It is assumed that the features of nonequilibrium-carrier recombination, which proceeds through several channels and depends on the excitation intensity and extraction electric field strength, can stem from the polycrystalline structure of the Cd0.8Hg0.2Te layers.