System of excitons bound at oxygen centers and stimulated emission of CdS crystals

Abstract

The paper presents the results of a study of the optical properties of CdS on the basis of the band anticrossing theory (BAC) with the involvement of the wider source data to the analysis results. Depending on the growth conditions, the presence and change in the concentration of oxygen and intrinsic point defects, which determine the composition of the crystals, have been taken into account. Data from studies of the structural features of crystals have also been used. The concept of nonuniform distribution of oxygen isoelectronic centers in the CdS volume due to their predominant segregation in layers of stacking faults (SFs) and also on dislocations has been introduced. To analyze the optical data, the capabilities of the method for constructing band models, which collect extensive and multilateral information about specific samples have been used. A refined model multizone of [Formula: see text] with SFs, which determines the spectrum of edge emission, has been presented. The nature of the edge emission A2B6 crystals with a small deviation from stoichiometry (CdS type) was explained as a spectrum of bound excitons at oxygen centers in SF layers. The article gives recommendations for the diagnostics of CdS crystals, suitable for creating stable luminescent systems or lasers.