Electroreflectance studies inMnxCd1−xSe

Low-field electroreflectance (ER) measurements are reported for ${\mathrm{Mn}}_x{\mathrm{Cd}}_{1-x}\mathrm{Se}$ ($0\le x\le 0.42$) from 1.2 to 2.7 eV. Three different structures are observed in the ER spectra, corresponding to the transition from the crystal-field— and spin-orbit—split valence bands to the conduction band. The dependence of the energy gap and crystal-field and spin-orbit splitting on the temperature and composition has been obtained from an analysis of the ER data. In the samples with higher Mn content, the high-energy ER structure, which may be due to the excitation of the Mn $3d$ states, is observed. The broadening parameter of the fundamental ER structure yields information about compositional homogeneity of the materials investigated.