GROWTH AND CHARACTERIZATION OF CD1-XMGXSE MIXED-CRYSTALS

Cd1-xMgxSe mixed crystals for 0 < x < 0.55 have been grown by the high -pressure Bridgman method under an argon overpressure. The dependence of the energy gap, the luminescence and the electrical properties on t he Mg concentration has been investigated. Luminescence and transmissi on spectra show that the band-gap energy is considerably larger than t hat of ''pure'' CdSe and for Cd0.45Mg0.55Se we measured about 2.82 eV at T = 40 K. As grown Cd1-xMgxSe solid solutions with x < 0.4 exhibit n-type conductivity and low electrical resistivity (p < 1 Omega cm at room temperature). The maximum of electron concentration 1.3 x 10(18) cm(-3) was obtained for Cd0.85Mg0.15Se. An attempt to explain the depe ndence of free-carrier concentration on composition by a model of Ferm i-level pinning is presented. (C) 1998 Elsevier Science B.V. All right s reserved.