Admittance Spectroscopy and Photoluminescence Characterization of High-Quality p-Type Cadmium Telluride

Abstract

Undoped high‐quality p‐type and Cu‐doped CdTe crystals are characterized by admittance spectroscopy (AS) and photoluminescence (PL) measurements in order to analyze the residual impurities. An improved method is proposed for the analysis of “freezing‐out steps” in AS. The method permits to determine the activation energies, the concentrations, and the compensation ratios of the uncompensated shallowest acceptors. Cross‐check using AS and PL indicates that the residual copper impurity strongly affects the electrical and optical properties of the high‐quality p‐type CdTe crystals.