Photoluminescence of ZnSe single crystals diffused with a group-III element

Abstract

Photoluminescence of ZnSe single crystals doped with group-III elements (Al, Ga, In) has been studied in order to obtain both a high blue luminescence quality and suitable conductance for making a luminescence diode. The highest-energy blue emission, which is the strong blue emission in electroluminescence at room temperature, is increased with Zn-Ga diffusion. The free-to-bound blue emission is enhanced and the self-activated orange emission is suppressed with Zn-Ga and Zn-In diffusion. The Zn-Al and Ga diffused crystals exhibit only the self-activated emission. Several characteristics of the recombination centers have been examined, including the temperature dependence of the emission peak energy, half-width, and emission intensity, as well as excitation spectra for these centers. Information gained from these studies concerning impurity levels and luminescence processes in impurity-doped ZnSe crystals is discussed.