Investigation of Electronic Structure of Zn_1-xMg_xMixed Crystals by Compton Spectroscopy Method

Abstract

The Ζn1-x Mgx Se crystals attract significant interest for their potential applications in technology of blue light-emitters (light emitting diodes and laser diodes) [1][2][3]. However, there is a little known about the fundamental properties of this material. This paper deals with the study of the Compton profiles of Ζn1-x Mgx Se crystals with x ranging from 0.25 to 0.56. Crystals were grown by the high-pressure Bridgman method. The crystals composition and stucture were verified by electron probe microanalysis and X-ray diffractometry. For the Compton investigations the crystals were cut perpendicularly to the crystal growth axis in 1 mm thick plates. Laue patterns show that different ingots of Ζn1-xMgxSe exhibit a usually different orientation. It was found that for a low concentration of Mg the Ζn1 -x Mgx Se crystallises in sphalerite form while for higher Mg concentrations in wurtzite one. The stuctural phase transition appears at x = 0.18 ± 0.03. For compositions close to the phase transition region a significant amount of stacking faults and of politypes is observed.Typical photoluminescence spectra of Zn1-xMgxSe consist of near-band-edge and deep levels emission which intensity ratio increases with increasing Mg content [4]. All as-grown Zn1-x Mgx Se crystals with high concentration of Mg exhibit high electrical resistivity [5,6]. The electronic stucture of the mixed crystals and the (907)