X-ray data are presented on high crystalline quality GaN grown on basa
l plane (0001) sapphire by MOCVD. An X-ray rocking curve displaying Pe
ndellosung fringes and having an FWHM of 27 s(-1) is reported for a 0.
7 mu m thick film. Reciprocal space mapping of the (0002) GaN reflecti
on is presented.