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 first reported. The deposition temperature is 950 degrees C, about 100 degrees C lower than that in normal rf-heating MOCVD growth. The FWHM of GaN (0002) peak of the X-ray diffraction rocking curve is 8.7 arc min. Photoluminescence spectrum of GaN film 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 GaN film is 1.7 x 10(18) cm(-3) and the Hall mobility of it is 121.5 cm(2)/V s. It is suggested that the radiation of light in GaN growth enhances the dissociation of ammonia and decreases the disadvantages of the parasite reaction between trimethylgallium and ammonia.