Author(s): Guo, D (Guo, Dan); Qiu, C (Qiu, Chen); Yang, KK (Yang, Kaike); Deng, HX (Deng, Hui-Xiong)

Source: PHYSICAL REVIEW APPLIED Volume: 15 Issue: 6 Article Number: 064025 DOI: 10.1103/PhysRevApplied.15.064025 Published: JUN 10 2021

Abstract: Nonradiative-recombination-related defects are significant for optoelectronic semiconductor devices. Here, we analyze nonradiative-recombination processes in ionic semiconductors using first-principles density-functional theory. In ionic group II-VI semiconductors, we find that large lattice relaxations of anion vacancies caused by strong Coulomb interactions between different charged defect states can significantly enhance recombination processes through a two-level recombination mechanism. Specifically, we show that the defect level of the 2+ charged anion vacancy (V2+Se ) in group II-VI ZnSe is close to the conduction-band minimum and easily captures an electron to form a metastable 1+ charged state (V+Se); then, the large lattice relaxation, on account of the change in Coulomb interactions locally in the different charged states, rapidly changes this metastable state to a stable one and simultaneously move the defect level of V+Se closer to that valence-band maximum, and thus, increases the hole-capture rate. Compared with the Shockley-Read-Hall nonradiative-recombination theory based on a single defect level, this two-level recombination mechanism involving anion vacancies can greatly increase the nonradiativerecombination rate in ionic group II-VI semiconductors. This understanding is expected to be useful for the study of the nonradiative-recombination process in ionic semiconductors for applications in the field of optoelectronic devices.

Accession Number: WOS:000663806000003

ISSN: 2331-7019

Full Text: https://journals.aps.org/prapplied/abstract/10.1103/PhysRevApplied.15.064025