The Influence of γ-Irradiation on the Current Transport Mechanism upon the Application of Reverse Bias to the Al/p-CdTe/Mo Structure
Annotatsiya
The influence of irradiation with γ-quanta on the current transport mechanism in the Al/p-CdTe/Mo structure was investigated. X-ray powder diffraction analysis determined the real structure of this material as Al/n-Al2O3/p-CdTe/n-MoO3/Mo. In its final form, it is represented as n+–p–n, where the base (p-CdTe) is in contact on both sides with wide-bandgap thin oxide layers of n-Al2O3 and n-MoO3 so that the n+–p junction is ideal and the p–n junction is nonideal. Upon the application of reverse bias (when a positive (+) voltage is applied to Al and a negative (–) to Mo), minority nonequilibrium charge carriers accumulate near the ideal contact, which results in an extended sublinear region in the reverse current–voltage characteristic of the structure before and after irradiation. This is explained within the framework of the theory of injection depletion effect by the injection of electrons from the rear junction n-MoO3/p-CdTe and by the emergence of diffusion and drift currents directed toward each other in the base of the structure. The shape and length of the sublinear region are preserved because of the high value of the frontal–ideal potential barrier n+–p, while in the range of various irradiation doses Φ (106, 107, 108, and 109 rad), the distribution profile of nonequilibrium charge carriers in the base of the structure remains virtually unchanged.