Influence of ammoniating temperature on Co-catalyzed GaN nanowires

GaN nanowires (NWS) were synthesized at different temperatures by ammoniating Ga₂O₃/Co films deposited on Si (111) substrate. X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscope (HRTEM), Fourier transformed infrared spectra (FTIR) and photoluminence (PL) spectra were used to characterize the influences of the ammoniating temperature on the morphology, crystallinity and optical properties of GaN NWS. Our results indicate that the samples are all of wurtzite structure and also show that the GaN NWS ammoniated at 950 °C have the best morphology and crystallinity with a single-crystalline structure, and at this temperature the PL spectrum with the strongest ultraviolet (UV) peak is observed. PACS 61.46.-w; 71.55.Eq; 81.15.Cd; 81.07.-b; 61.10.Nz