Fabrication and photoluminescence properties of silicon nanowires with thin surface oxide layers

Si nanowires have been synthesized by a novel oxide-assistant growth mechanism using boron powder and silicon oxide as reactants. Their structures and morphologies have been investigated using X-ray diffraction, scanning and transmission electron microscopy, energy-dispersive X-ray spectroscopy, and electron energy loss spectroscopy. The obtained nanowire consists of a single-crystalline Si core and a very thin amorphous boron oxide layer. Photoluminescence investigations reveal that the Si nanowires possess a broad red emission band. The outside amorphous oxide layer plays an important role for the luminescence. The study suggests that the Si nanowires can find potential applications in nanoscale electric and optoelectronic devices.