Improved Carrier Lifetime in BiVO4 by Spin Protection

Mechanistic understanding of the effect bulk defects have on carrier dynamics at the quantum level is crucial to suppress associated midgap mediated charge recombination in semiconductors yet many questions remain unexplored. Here, by employing ab initio quantum dynamics simulation and taking BiVO4 with oxygen vacancies (Ov) as a model system we demonstrate a spin protection mechanism for suppressed charge recombination. The carrier lifetime is significantly improved in the high spin defect system. The lifetime can be optimized by tuning the Ov concentration to minimize the nonradiative relaxation. Our work addresses literature ambiguities and contradictions about the role of bulk Ov in charge recombination and provides a route for defect engineering of semiconductors with enhanced carrier dynamics.

Automated summary

This study employs ab initio quantum dynamics simulation to investigate the effect of bulk defects on carrier dynamics in semiconductors. By using BiVO4 with oxygen vacancies as a model system, a spin protection mechanism for suppressing charge recombination is demonstrated. The results show that the carrier lifetime is significantly improved in the high spin defect system, and can be optimized by tuning the oxygen vacancy concentration to minimize nonradiative relaxation. This work addresses ambiguities in the literature and provides a route for defect engineering of semiconductors with enhanced carrier dynamics.