Structural and Energetic Analysis of Group V Impurities in p-Type HgCdTe: The Case of As and Sb

Although molecular beam epitaxy technology-based arsenic-doped Hg1-x Cd (x) Te has been extensively studied, according to the newly proposed framework of the defect-complex-based p-type doping mechanism, heavier group V elements such as antimony (Sb) should have a different doping behavior because of their larger radius which can cause larger lattice distortion. In this work, we performed first-principles calculations and took As and Sb as examples to study this issue. The substitutional doping, interstitial doping (including split, tetrahedral, and hexagonal interstitial sites), and defect complex doping forms for arsenic and antimony are all investigated. A significant lattice distortion is found in hexagonal and split-site interstitial-Sb-doped Hg0.75Cd0.25Te due to the larger covalent radius of Sb. Compared with As, Sb can lead to a more complicated configuration change in the case of Sb-Hg-V (Hg)-Sb-Hg tridoping, and the interstitial Sb is found to be stable even with the coupling of Hg vacancies through detailed energetic calculations, indicating that the interstitial Sb has greater ability to form stable defect complexes, and thus great potential to be a more appropriate p-type dopant. This study provides more complementary understanding of the behaviors of group V impurities in HgCdTe.