Nonradiative Dynamics Induced by Vacancies in Wide-Gap III-Nitrides: Ab Initio Time-Domain Analysis

Insightful understanding of defect properties and prevention of defect damage are among the biggest issues in the development of photoelectronic devices based on wide-gap III-nitride semiconductors. Here, we have investigated the vacancy-induced carrier nonradiative dynamics in wide-gap III-nitrides (GaN, AlN, and AlGa_1-N) by ab initio molecular dynamics and nonadiabatic (NA) quantum dynamics simulations since the considerable defect density in epitaxy samples. E-h recombination is hardly affected by V_cation, which created shallow states near the VBM. Our findings demonstrate that V_N in AlN creates defect-assisted nonradiative recombination centers and shortens the recombination time (τ) as in the Shockley-Read-Hall (SRH) model. In GaN, V_N improves the NA coupling between the CBM and the VBM. Additionally, increasing x in the AlGa_1-N alloys accelerates nonradiative recombination, which may be an important issue in further improving the IQE of high Al-content AlGa_1-N alloys. These findings have significant implications for the improvement of wide-gap III-nitrides-based photoelectronic devices.