One-dimensional GaN nanostructures prepared via chemical vapor deposition: Substrate induced size and dimensionality

Large-scale uniform one-dimensional (1D) GaN nanostructures have been successfully synthesized via the chemical vapor deposition method. The type of substrate was found to be a crucial factor in the synthesis of GaN, it affects the shape as well as the diameter of the formed nanowires, and nanorods. It was noticed that the size and dimensionality were the most influential on structural and optical properties of the grown GaN. X-ray diffraction confirms the formation of hexagonal wurtzite structure where the lattice parameters vary with the type of substrate. Similarly, transmission electron microscopy observations reveal the formation of different morphologies: nanowires for Si-substrate; nanorods for AlN and Al2O3-Substrate. Photoluminescence spectra of GaN nanostructures showed two peaks at a near-band-edge (NBE) emission in the ultraviolet region and a broad emission around the red emission (RE). The crystallinity of product materials and defects in the crystal structure were studied through Raman spectroscopy.