Role of excited states in Shockley-Read-Hall recombination in wide-band-gap semiconductors

TL;DR

This paper reveals that electronic excited states significantly influence defect-assisted nonradiative recombination in wide-band-gap semiconductors, especially in group-III nitrides, impacting optoelectronic device efficiency.

Contribution

It uncovers the crucial role of excited states in nonradiative recombination, providing new insights into defect physics in wide-band-gap semiconductors.

Findings

Excited states facilitate nonradiative recombination in wide-band-gap materials.

Defect-assisted recombination limits efficiency in group-III nitrides.

Insights are applicable broadly to wide-band-gap semiconductors.

Abstract

Defect-assisted recombination is an important limitation on efficiency of optoelectronic devices. However, since nonradiative capture rates decrease exponentially with energy of the transition, the mechanisms by which such recombination can take place in wide-band-gap materials are unclear. Using electronic structure calculations we uncover the crucial role of electronic excited states in nonradiative recombination processes. The impact is elucidated with examples for the group-III nitrides, for which accumulating experimental evidence indicates that defect-assisted recombination limits efficiency. Our work provides new insights into the physics of nonradiative recombination, and the mechanisms are suggested to be ubiquitous in wide-band-gap semiconductors.