Investigation on minority carrier lifetime, diffusion length and recombination mechanism of Mg-doped GaN grown by MOCVD

Abstract

Minority carrier lifetime and diffusion length are important parameters for GaN based material and devices. In this work, we obtained the minority carrier lifetime and diffusion length of p-GaN through the photoluminescence lifetime of the band edge peak, and analyzed the recombination behavior of carriers. Besides, the dependence of photoluminescence lifetime of GaN: Mg grown by MOCVD on annealing temperature (TA) and Mg concentration ([Mg]) has been investigated through Time-resolved Photoluminescence (TRPL) measurements. We increased the activated Mg acceptors ratio by increasing TA, analyzed the fast and slow decay of carrier recombination, and compared the effects of annealing on the lifetime of GaN band-edge emission with different Mg concentrations. And it is found that the minority carrier lifetime in p-GaN is not only related to Mg concentration, but also related to the activated Mg acceptors concentration / hole concentration. Meanwhile, we compared heteroepitaxial p-GaN with homoepitaxial p-GaN, and further analyzed the influence of dislocation as non-radiative recombination centers (NRCs) on carrier lifetime and recombination behavior.