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-cross-sections 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 V Ga V N divacancies, being 7 × 10 −14 cm 2 .