Two differing trends of plasma damage in n-type GaN were observed. Two modes of etching behaviour were attributed to the presence of Ga vacancies in the material. The resistivity of GaN with Ga vacancies increased during plasma exposure, due to electrical compensation via the formation of deep acceptor states as a result of vacancy-complex formation. Samples which were free of Ga vacancies underwent a reduction in resistivity as N vacancies were produced by interaction with the plasma. The results correlated well with photoluminescence spectra, where a significant yellow-band emission was detected from samples with a high concentration of Ga vacancies.

The Link between Gallium Vacancies and Plasma Damage to n-Type GaN. H.W.Choi, S.J.Chua: Physica Status Solidi A, 2001, 188[1], 393-7