Effects of annealing temperature on the properties of GaN films on Si substrates

GaN films were fabricated on Si (111) substrates by electrophoretic deposition (EPD) technique, and the effects of the annealing temperature on the crystal quality, morphology and optical property of the GaN films are investigated. The measurements of the Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) indicate that the as-grown films are polycrystalline GaN with hexagonal wurtzite structure, moreover, the diameters of the GaN crystallites become larger and the crystal quality of the GaN finis is improved with the increase of annealing temperature. Photoluminescence (PL) spectra at room temperature show a very strong emission peak at 367 nm and a weak emission peak at 437 nm. When raising the annealing temperature, the two emission peaks become more intense, while their locations don't change.