A method of growing semipolar GaN on m-plane sapphire substrate using metalorganic chemical vapor deposition (MOCVD) is described. A suitable m-plane Al2O3 is used as substrate. Nitridation of substrate is performed at growth temperature with gaseous H2 and NH3 flow. After a desired time has elapsed, growth of planar m-plane GaN layer on the substrate is performed with gaseous (Ga(CH3)3), H2 and NH3 flow. Semipolar m-plane GaN is grown on the substrate. The surface morphology of semipolar GaN has improved as captured by atomic force microscope and scanning electron microscope.