The effect of carbon incorporation on luminescence properties of GaPN grown by organometallic vapor phase epitaxy (OMVPE) has been investigated. Trimethylgallium (TMGa) and trimethylgallium (TEGa) were used as Ga precursors. The carbon concentration of 1.1×1017cm–3 was obtained by using TEGa, whereas that of GaPN grown using TMGa was 4.0×1017cm–3. Non‐radiative recombination rate was also reduced to about 1/100 by using TEGa. Moreover, the spatial fluctuation of N content and Non‐radiative rate was reduced with increasing substrate temperature. Therefore, luminescence properties of GaPN could be improved by using TEGa at high substrate temperature. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)