Effect of erbium on the luminescence properties of GaSb crystals

Abstract

The interest of rare earth doping of semiconductors has increased in the last years due to its possible applications in optical devices requiring temperature stability. Advantages of these systems are the presence of a sharp temperature independent rare-earth luminescence and the possibility of activation of the emitting rare-earth centers by minority carrier injection. In this work the effect of erbium doping on the luminescence and on the native accepters of GaSb crystals has been investigated by CL-SEM. Er doping has been found to increase the total CL intensity and to produce spectral changes that depend on the erbium concentration. At moderate doping the native acceptor concentration, as detected by the luminescence band A, decreases. At high Er concentrations Er-Sb precipitates form and doping appears not to be efficient in the suppression of accepters. X-ray microanalysis reveals that the composition of the precipitates is Er-5 Sb-3. Emission from intraionic transitions of Er is observed in highly doped crystals.