Deep Acceptor Levels in Rb – Doped CdS and CdS1-x Sex Single Crystals Revealed by Optical Quenching Spectroscopy: Temperature Dependence and Photoinduced Effects

Abstract

Optical quenching (OQ) of photoconductivity is an established spectroscopic approach for investigating deep electronic centers that participate in carrier trapping and recombination in II-VI semiconductors. The present study analyzes the optical-quenching and temperature-dependent photoconductivity behavior of Rb – Doped CdS and CdS_1-x Se_x  single crystals. The experimental data used in Table 1 originate from the author's doctoral experimental research and are retained as the basis for a focused analytical treatment. The present study represents an analytical and interpretative extension of the original experimental investigation, rather than a new experimental campaign. The analysis indicates two characteristic energy regions associated with deep acceptor-related processes: approximately E_v + 0.60 eV, associated with thermal activation of photoconductivity, and approximately  E_v + 1.0 eV, associated primarily with the optical-quenching response. The OQ intensity decreases with increasing temperature and disappears above approximately , while the temperature dependence of steady-state photoconductivity provides an activation energy close to 0.60 eV. The optical response near 1.0 eV becomes more pronounced following photoinduced chemical reactions (PhCR), indicating sensitivity of the defect subsystem to illumination history. The present analysis provides a focused analytical extension of the original doctoral investigation by integrating the thermal and optical signatures of the deep centers within a unified energy-level interpretation.