Fabrication of crystal α-Si 3N 4/Si-SiO x core-shell/Au-SiO x peapod-like axial double heterostructures for optoelectronic applications

Novel crystal α-Si 3N 4/Si-SiO x core-shell/Au-SiO x peapod-like axial double heterostructural nanowires were obtained by directly annealing a Au covered SiO 2 thin film on a Si substrate. Our extensive electron microscopic investigation revealed that the α-Si 3N 4 sections with a 101 growth direction were grown first, followed by growth of the Si-SiO x core-shell sections and finally growth of the Au-SiO x peapod-like sections. Through a series of systematically comparative experiments, a temperature-dependent multi-step vapor-liquid-solid growth mechanism is proposed. Room temperature photoluminescence measurement of individual nanowires reveals two emission peaks (410 and 515nm), indicating their potential applications in light sources, laser or light emitting display devices.