Composition dependence of the unit cell dimensions and the energy gap in Zn_1-xMg_xSe crystals

Abstract

Zn,+Mg,Se mixed crystals were grown by the high-pressure Bridgman method in the x range 0.06 to 0.285. X-ray investigations show that with increasing Mg content the transition from a sphalerite structure to wurtzite occurs at x = 0.185 4 0.03. After annealing in liquid zinc or zinc vapour, investigated crystals exhibit n-type conductivity as well as blue-violet and orange photoluminescence in the temperature range from 40 K to room temperature.

Raman Analysis of Zn1-xMgxSe Layers Grown on GaAs and ZnTe Substrates

“…3) [3,8,9]. The occurrence of both the LOZn-Se and LOMg-Se vibrational modes is typical for the two-mode behaviour of the Zn 1 -x Mgx Se crystals.…”

“…The occurrence of both the LOZn-Se and LOMg-Se vibrational modes is typical for the two-mode behaviour of the Zn 1 -x Mgx Se crystals. Since the energy Eg of Ζn1-x Mgx Se also depends on the Mg content in the layer [5,8,9], the choice of the excitation energy is of cucial importance in order to obtain the optimum signal intensity. Moreover, for strained layers grown at different temperatures possible ad ditional frequency shifts have to be taken into account.…”

Raman Scattering in Zn1-xMgxSe Mixed Crystals

“…It has been also observed in Zn1-x Mg x Τe [8,9], Cd1-x MgxΤe [10] and Zn1-x Mgx Se [11,12]. Some preliminary results on photoluminescence and electrical properties of Ζn1-x Mgx Se bulk crystals have been already published [5,6].…”

“…This lighter component exhibits a vibrational mode (local mode) with a frequency higher than that of the perfect crystal. Such behaviour can be expected for Zn1-x Mg x Se mixed crystal which is lately extensively studied because of potential application in constructing blue and UV light sources [3][4][5][6]. However, no experimental data for Ζn1-x Mgx Se bulk crystals are available until now.…”

“…The following data were taken for calculations: TO (ZnSe) = 205 cm -1 , LO (ZnSe) = 251 cm -1 , ε∞ (ZnSe) = 9.2. The following linear dependence of cubic lattice constant on Mg content x were used: α(x) = 5.67 + 0.22x Α [5,6]. In the applied MREI model we estimated all parameters of pure MgSe to fit the computed values to experimental data, since these data for MgSe are not known.…”