Metastable photoluminescence in heavily Mg-doped GaN grown by metalorganic chemical vapor phase epitaxy

Abstract

The long-term transient spectra of heavily Mg-doped GaN have been investigated. As the excitation power density increased, the broad Mg-induced emission band showed blue-shift revealing characteristic of donor-acceptor pair (DAP) recombination. We also observed an unusually slow intensity decay. The characteristic time constants range from several tenths to a few hundred seconds for emission between 360 and 460 nm. Our results are interpreted in terms of metastability due to compounded effects of differential DAP population and recombination rates and uneven acceptor distribution.