Thermodynamics and crystal growth of Cd1-x-yMnxZnyTe (x=0.10, 0.20, y=0.15)

Abstract

In this work the structural, optical and electrical properties of Cd1-x-yMnxZnyTe single crystals (x=0.10, 0.20, y=0.15) grown by the vertical Bridgman method were investigated. Based on differential thermal analysis (DTA) results, it was found that the crystallization rate increases as the crystallization temperature (Ts) decreases. It is determined that the volume fraction of solid phase in Cd0.75Mn0.10Zn0.15Te and Cd0.65Mn0.20Zn0.15Te alloys decrease to a minimum in the temperature ranges 1366-1389 K and 1363-1388 K, respectively. The activation energies of melting and crystallization processes for these alloys under different conditions are established. The linear character of the dependence between the preexponential factor (lnϕsol.phase,0 and lnVmelt., sol. phase,0) and the activation energy of these processes is determined, which is evidence of a compensation effect. The band-gap value was estimated to be ~ 1.73 eV for Cd0.75Mn0.10Zn0.15Te and ~1.84 eV for Cd0.65Mn0.20Zn0.15Te at 300 K. Typical transmission images showed the presence of small Te inclusions (5-10 µm) in the crystals. The electrical resistivity, obtained from the I-V curves, was ~10 4 Ώ•cm for both crystals and decreased slightly toward the end of the ingots.