AbstractEpitaxial layers of GaN have been grown on {1102} sapphire in atmospheric OMCVD system using Ga(CH3)3· N(CH3)3adduct and NH3as reactants. Optimum growth conditions for crystallographically perfect layers have been found at temperatures between 850 and 1000 °C. With increasing temperature the growth rate decreases whereas the concentration of free carriers increases. In photoluminescence spectra only the donor‐acceptor pair recombination could be found. It is concluded that the donor oxygen (ON) and the acceptor carbon (CN) are the dominant impurit