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_Gas) and N vacancies (V_Ns), 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.