Fabrication and characterization of Si₃N₄ nanostructures with different morphology

Single crystalline Si₃N₄ nanowires and nanobelts have been synthesized by vapor-liquid-solid (VLS) and vapor-solid (VS) mechanism respectively. Their morphologies and microstructures were determined by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The FTIR spectra of them show a broad absorption band in the range of 800-1100 cm^-1 which corresponded to the stretching vibration absorption peaks of the Si-N. Photoluminescence (PL) measurements of them under excitation at 280 nm at room temperature show a broad blue emission band at about 420 nm, suggesting their potential applications in light emission nanodevices. In addition, the peak position of Si₃N₄ nanowires had blue shift according to the peaks of Si₃N₄ nanobelts, which might be related to the dimension difference between them. The results also show the PL intensity of the nanobelts was stronger than that of nanowires which might be resulted from the different defect concentrations.