GaN layers were grown on (0 0 0 1) sapphire substrates by saturating Ga metal with atomic nitrogen and hydrogen mixture in a microwave plasma operating at 1000 Pa with the power of 380 W to avoid high equilibrium pressure and temperature environment. The semi-transparent GaN layer of about 3 mu m was grown on the substrate at a growth rate of 0.6 mu m/h under hydrogen flow ratio of 50%. The film had luminescence property without a deep level yellow emission. These results indicate that the direct conversion of Ga metal into GaN layer under nitrogen plasma is a useful method. (C) 2008 Published by Elsevier B.V.