Growth of wurtzite GaN films on #alpha#-Al_2O_3 substrates using light radiation heating metal-organic chemical vapor deposition

摘要

Epitaxial growth of high quality hexagonal GaN films on sapphire substrates using light radiation heating metal-organic chemical vapor deposition (LRH-MOCVD) is firstly reported. The deposition temperature is 950 deg, about 100 deg lower than that in normal rf-heating MOCVD growth. The FWHM of GaN (0002) peak of x-ray diffraction rocking curve is 9.8 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 1.7x10~(18) cm~(-3) and the Hall mobility of it is 121.5 cm~2/V.s. It is suggested that the radiation fo light in GaN growth enhances the dissociation of ammonia and decreases the disadvantages of the parasite reaction between trimethylgallium and ammonia.