Effect of V-Pits on the Property of GaN Epilayer Grown by Metalorganic Chemical Vapor Deposition

Revealing the effect of the V-pits on the property of GaN is the key to understand and control the defects and thus to improve the performance in the GaN based devices. Here, the influence of the V-pits on the morphology, optics, structure and strain properties of GaN epilayer was investigated. The GaN films with different V-pits density were obtained by changing the growth parameters of metalorganic chemical vapor deposition. The scanning electron microscope, photoluminescence, high resolution X-ray diffraction and Raman were used to character the influence of V-pits on the GaN film. The results show that the sidewalls of V-pits might have higher bandgap than that of flat areas, which can suppress the shallow donor level related radiation recombination. Moreover, the V-pits can release the stress without apparently destroying the structural property. The results obtained here have importance of direction in controlling and taking advantage of V-pits.