Exciton localization in Mg_xZn_yCd_1−x−ySe alloy

Abstract

PACS 78.30.Fs, 78.40.Fy, 78.55.Et We report photoluminescence and reflectivity measurements of Mg x Zn y Cd 1-x-y Se epitaxial layers (0 < x < 0.53) grown by molecular beam epitaxy on InP (100) substrates. Significant emission line broadening, increase in activation energy and Stokes shift are monitored with increasing Mg content. For Mg x Cd y Zn 1-x-y Se samples with large Mg content (x > 0.3), we observe an anomalous temperature dependence of both the emission energy and line broadening. This behavior is assigned to the emission from localized states. Different mechanisms of carrier localization are discussed and exciton localization on statistical CdSe clusters is proposed to be the most likely one.