We report that a H-2-free atmosphere is essential for the initial stage of metalorganic vapour phase epitaxy (MOVPE) growth of GaN on beta-Ga2O3 to prevent the surface from damage. A simple growth method is proposed that can easily transfer established GaN growth recipes from sapphire to beta-Ga2O3 with both (-201) and (100) orientations. This method features a thin AlN nucleation layer grown below 900 degrees C in N-2 atmosphere to protect the surface of beta-Ga2O3 from deterioration during further growth under the H-2 atmosphere. Based on this, we demonstrate working violet vertical light emitting diodes (VLEDs) on n-conductive beta-Ga2O3 substrates. (C) 2017 Elsevier B.V. All rights reserved.