Anharmonic multi-phonon nonradiative transition: A n ab initio calculation approach

摘要

Nonradiative carrier recombinations at deep centers in semiconductors are of great importance for both fundamental physics and device engineering.In this article,we provide a revised analysis of Huang''s original nonradiative multi-phonon(NMP)theory with ab initio calculations.First,we confirmed at the first-principles level that Huang''s concise formula gives the same results as the matrix-based formula,and that Huang''s high-temperature formula provides an analytical expression for the coupling constant in Marcus theory.Secondly,we correct for anharmonic effects by taking into account local phonon-mode variations for different charge states of a defect.The corrected capture rates for defects in GaN and SiC agree well with experiments.