Growth of wurtzite GaN films on α-Al2O3 substrates using light radiation heating metal-organic chemical vapor deposition

Epitaxial growth of high quality hexagonal GaN films on sapphire substrates using light radiation heating metal-organic chemical vapor deposition (LRH-MOCVD) is reported. The deposition temperature is 950°C, about 100°C lower than that in normal rf-heating MOCVD growth. The FWHM of the GaN (0002) peak of X-ray diffraction rocking curve is 9.8 arc min. The photoluminescence spectrum of GaN shows that there is a very strong band-edge emission and no “yellow-band” luminescence. Hall measurement indicates that the n-type background carrier concentration of the GaN film is 1.7×10¹⁸ cm^-3 and the Hall mobility is 121.5 cm²/V.s. It is suggested that the radiation of light in GaN growth enhances the dissociation of ammonia and decreases the disadvantages of the parasitic reaction between trimethylgallium and ammonia