Dislocation Luminescence in ZnSe

Abstract

Thin film, high purity II-VI semiconductors such as ZnSe are attracting increasing interest as optoelectronic device materials. Recent developments in low temperature epitaxial growth techniques such as organometallic chemical vapour deposition (MOCVD) have enabled growth of single crystal films on a variety of different substrates resulting in blue emission bands at 300K. Characterization of undoped, Al-doped and In-doped MOCVD ZnSe/(100)GaAs layers grown at RSRE, Malvern has been performed using transmission electron microscopy (TEM) and cathodoluminescence (CL). Optically and electrically active stacking faults and dislocations have been observed, revealing correlations with emission bands Y at 2.60eV and S at 2.52eV. Y and S are particularly characteristic of epitaxial growth and radiative emission has been observed from individual dislocations and complex tangles of dislocations commonly found in doped ZnSe. Recent work has concentrated on obtaining an understanding of the mechanism of radiative recombination at dislocations by studying thermal activation energies and excitation dependences.