Differential thermal analysis of supercooling in CdTe

Abstract

The supercooling of the melt before the start of crystal growth depends on the previous overheating of the liquid, stoichiometry of the melt, and cooling rate. Differential thermal analysis (DTA) scanning experiments were performed for different cooling rates under constant Cd vapor pressures, which were varied from 1 atm to 5 atm. The maximum cooling rate was 1 K/min and the minimum was 0.05 K/min. It was found that the degree of supercooling systematically decreases with increasing of Cd vapor pressure and near 4-5 atm practically approaches zero. This complex behavior could be explained by a structural alteration in the state of the CdTe melt during stepwise changing of its stoichiometry from Te-to Cd-rich.

Solid↔liquid Cd(Zn)Te phase transition correlative analysis

“…The electrical conductivity temperature dependences' s(T) parameters for the CdTe-related melts investigated in various thermodynamical and kinetic conditions by different experimental methods [10,[13][14][15] (Fig. 3) also show their validity to the compensation rule.…”

“…Various methods have been used today for investigation of the CdTe and CdZnTe melts transformation with increasing and decreasing temperature: electrical conductivity [1][2][3][4][5][6], thermo power [3,5], viscosity [7,8], differential thermal analysis [9][10][11][12] and others. It was shown that the crystals melting process occurs step-by-step with rapid transformation of creating structural units at certain temperatures [2,3,8].…”