Defect Equilibria in In- and Ga-Doped CdTe

Abstract

The Hall coefficient of four CdTe samples with [In] = 5 × 1016 to 1019 cm–3 and two CdTe samples with [Ga] = 4 × 1017 and 1.4 × 1018 cm–3 was measured between 700 and 1300 K at a controlled Cd vapor pressure. The equilibrium constant of In incorporation into CdTe from In precipitates was calculated. Kroger's quasi-chemical equations were used to evaluate the concentrations of point defects as a function of temperature and dopant activity. The results agree well with experimental data. The maximum in the temperature dependence of electron concentration is interpreted in terms of the competition between the increase in the concentration of D Cd + donors as a result of the increase in dopant solubility and the compensation of the donors by native acceptors (V 2- Cd) and impurity-containing acceptor complexes (A In - or A Ga -). Modeling results confirm that the formation of these complexes is due primarily to Coulombic interaction.