Room temperature photoluminescence lifetime for the near-band-edge emission of epitaxial and ion-implanted GaN on GaN structures

For accelerating the development of GaN power-switching devices, current knowledge on the origins and dynamic properties of the major intrinsic nonradiative recombination centers (NRCs) in Mg-doped GaN (GaN: Mg) are reviewed, as lightly to heavily doped p-type planar GaN segments are required but certain compensating defects including NRCs hinder their formation. The results of complementary time-resolved photoluminescence and positron annihilation spectroscopy measurements on the epitaxial and ion-implanted GaN: Mg formed on low dislocation density GaN substrates indicate the following: major intrinsic NRCs are the clusters of Ga vacancies (V(Ga)s) and N vacancies (V(N)s), namely V-Ga(V-N)(2) in the epitaxial GaN: Mg and (V-Ga)(3)(V-N)(3) in the ion-implanted GaN: Mg after appropriate thermal annealings. The minimum electron capture-crosssections of V-Ga(V-N)(2) and (V-Ga)(3)(V-N)(3) are commonly the middle of 10(-13) cm(2) at 300 K, which is approximately four times larger than the hole capture-cross-section of the major intrinsic NRCs in n-type GaN, namely VGaVN divacancies, being 7 x 10(-14) cm(2). (C) 2019 The Japan Society of Applied Physics