Defect equilibrium and complex formation in CdTe(Sn)

Abstract

Thermodynamic properties of native defects and their interactions with extrinsic defects including complex formation are studied theoretically and experimentally in Sn-doped CdTe. The high temperature (500–1000 °C) in-situ galvanomagnetic measurements at defined thermodynamic conditions are used to control defect equilibrium and electrical properties of annealed samples. Defect reactions are studied during the cooling of samples down to room temperature in the regime of slow diffusion where stoichiometry and doping density are fixed but the densities of different defect configurations change. The theoretical description of defects is based on the quasichemical formalism. We show that the analysis which includes two native defects Cd interstitial CdI and Cd vacancy VCd and three Sn related defects SnCd, SnI, and (SnCdVCd) allows to describe all principal experimental features and to reach good agreement of the theory with experiment. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)