Studying the Structure and Lifetime of Photogenerated Current Carriers of Cadmium Telluride-Based Solid Solutions in CdTe–Sb2Te3 and CdTe–CdSb Systems

Abstract

The structure of CdTe–Sb₂Te₃ and CdTe–CdSb solid solutions (0–10¹⁹ Sb atoms cm^–3) prepared by multistage solid-state synthesis from the elements has been studied. It has been found that the introduction of antimony Sb³⁺ and Sb³⁻ into cadmium telluride leads to a decrease and increase in the unit cell volume, respectively. It has been shown that the crystal lattice parameters gradually change up to an antimony concentration of 10¹⁸ atoms cm^–3 in both systems, whereas an increase in the antimony concentration above 10¹⁸ Sb atoms cm^–3 is characterized by an abrupt change in the unit cell volume due to a significant change in the structure. The decay kinetics of current carriers has been studied by the time-resolved microwave photoconductivity method. It has been found that the introduction of antimony into CdTe in a threshold concentration (10¹⁸ Sb atoms cm^–3) leads to an increase in the lifetime of photogenerated current carriers; this fact can be attributed to the formation of defect associates and the occurrence of a self-compensation process during doping.