Band anticrossing effects in MgyZn1-yTe 1-xSex alloys

The electronic structures of Mg_yZn_1-yTe _1-xSe_x alloys were studied by optical absorption and photoluminescence techniques under applied hydrostatic pressure. In samples with both x and y≠0, the band gap exhibits a strongly nonlinear pressure dependence which is similar to the effects observed previously in ZnTe _1-xSe_x and ZnTe_1-xS_x ternaries and that is well explained by the anticrossing interaction of the selenium localized electronic states with the conduction band of the matrix. In contrast, the pressure dependence of the band gap in Mg_yZn_1-yTe (i.e., x=0) is not significantly changed in form from that of ZnTe; it is concluded that the effects of alloying MgTe with ZnTe can be well understood within the virtual crystal approximation. © 2002 American Institute of Physics.