Construction, characterization, and growth mechanism of high-density jellyfish-like GaN/SiOxNy nanomaterials on p-Si substrate by Au-assisted chemical vapor deposition approach

Abstract

High-density, well-aligned GaN/SiO_xN_y nanomaterials with jellyfish-like shape are constructed on Au-coated p-type (111) Si substrates by a convenient chemical vapor deposition method. The morphology, structure, constituents and optical properties of the as-prepared nanomaterials are characterized through field-emission scanning electron microscopy, X-ray diffraction, field-emission transmission electron microscopy, energy-dispersive spectroscopy mapping, and photoluminescence spectroscopy. The systematic characterization results reveal that the high-density jellyfish-like nanomaterials are composed of single-crystalline GaN nanoblocks as jellyfish top-caps with size of 200–600 nm and amorphous SiO_xN_y nanowires as jellyfish bottom-tentacles with length of several micrometers. A growth mechanism of the jellyfish-like nanomaterials is proposed: Au acts as a capture site for the Ga species from vapor to form Ga–Si alloys, and then the Ga-catalyzed vapor–liquid–solid growth initializes the nucleation and further promotes the growth of silicon dioxide nanowires on the substrate surface; finally, the silicon dioxide nanowires with Ga balls are converted to form the high-density aligned GaN/SiO_xN_y jellyfish-like nanocomposites by nitridation. The GaN/SiO_xN_y jellyfish-like unique nanostructures grown on a p-type Si substrate will provide a new GaN-based device structure and offer potential applications in photocatalytic and optoelectronic nanodevices.