One-dimensional structures formed by low-temperature slip of dislocations that act as sources of dislocation absorption and emission in II–VI semiconductor crystals

Abstract

This paper presents and analyzes the results of measurements of characteristic narrow optical absorption and emission lines caused by low-temperature (at T=1.8–77 K) slip of dislocations in cadmium sulfide crystals. The optical absorption lines are characterized by giant oscillator strengths (f∼1). A model which explains the entire set of experimental results for cadmium sulfide and other II–VI compounds is proposed and substantiated. The proposed model associates the dislocation optical absorption and dislocation emission with the formation of one-dimensional chains of associates of point defects accompanying the slip of screw dislocations with jogs. The experimental data are used to calculate the linear density of jogs and the volume density of point defects in the chains, and the oscillator strengths of the corresponding optical transitions are also estimated.