The effects of substrates on the geometry and optical properties of aluminum nitride nanowires.

Based on a Chemical Vapor Deposition (CVD) process, an alumina tube electric furnace was assembled to synthesize different one dimensional aluminum nitride (AIN) nanostructures via aluminum powder and nitrogen gas flow. The products obtained where nanowires, nanorods, a unique chain-linked nanocage structure made from an entanglement of AIN nanowires and an interesting micro-sized spherical architecture. The different growth parameters dictated to the system result the product variety, making structure tuning possible. The incorporation of different substrates (silicon and alumina) not only leads to the formation of different shaped structures, but also results different optical emissions ranging from 450 nm (blue) to 650 nm (red), indicating the high potential of AIN nanostructures in LED fabrication. Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Selective Area Electron Diffraction (SAED), X-ray Diffraction (XRD), Photoluminescence (PL) and Energy Dispersive X-ray (EDX) analysis results are discussed and a Vapor-Liquid-Solid (VLS)/Vapor-Solid (VS) based growth mechanism is proposed for the mentioned structures.