Preparation and Microstructure Analysis of GaN Nanowires with the Sol-Gel Method

The two-step method, which includes the sol-gel process and ammoniation in high temperature, is used to synthesize GaN nanomaterials on Si (111) substrate. Ga(NO₃)₃ was used as gallium source, citric acid as the chelating agent and nickel nitrate as catalyst. After the sol can be formed by mixing ethanol solutions of Ga(NO₃)₃ and citric acid, the precursor films were coated on Si slices with or without the catalyst. and the dried samples are treated in ammonia at different temperatures in an atmosphere furnace. X-ray diffraction instrument (XRD) indicates that the as-prepared samples are hexagonal GaN, and scanning electron microscope (SEM) reveals that the microstucture morphologies of samples are crystal, nanorods and nanowires, and then high-resolution transmission electron microscopy (HTEM) were used to characterize the as-synthesized nanowire is of single-crystalline hexagonal wurtzite structure. The conclusion can be drawn that the catalyst and ammoniation temperature can influence greatly on the microstucture and shape features of as-synthesized GaN samples .