Photoluminescence spectra of GaN grown by metalorganic chemical-vapor depos
ition on sapphire show that by reactive ion etching, the intensity of the y
ellow luminescence (YL) band decreases compared to that of the as-grown GaN
, due to nonradiative recombination at the damage-induced defect centers. T
he intensity of the YL in dry-etched GaN has been found to be dependent on
rf power and postetch annealing. No change in intensity is observed with fu
rther etching indicating a uniform spread of yellow emitters in the epilaye
r which supports the view that point defects like V-Ga are the origin of th
e YL. (C) 1999 American Institute of Physics. [S0003-6951(99)00949-3].