Abstract:The crystal loops of Gallium nitride (GaN) were deposited on silicon (111) substrate by using hot-wall chemical vapor deposition and thermal treatment. Scanning electron microscopy (SEM), selected area electron diffraction (SAED), x-ray diffraction (XRD), photoluminescence (PL) and Fourier Transform Infrared transmission (FTIR) Spectroscopy were employed to analyze the surface morphology, structure and optical properties of GaN layer. SEM image shows five half-loops attached to a crystal string side by side in the uniform films. XRD, SAED patterns reveal that the formed loops are polycrystalline hexagonal gallium nitride. FTIR pattern shows the main composition of the film is GaN and it contains trifle carbon contamination. New feature is found in PL pattern of the crystal loops, which is different from the bulk GaN films.