Large-Scale Production of Amorphous Silicon Oxynitride Nanowires by Nickel-Catalyzed Transformation of Silicon Wafers in NH3Plasma

Amorphous silicon oxynitrides (a-SiOxNy) were prepared through thermal treatment of nickel coated silicon wafers in NH3plasma. Ni−Si alloy nanoparticles were formed at elevated temperature and served as the Si transfer medium from silicon wafers to nanowires. Without plasma, either amorphous silica (a-SiOx) nanowires or NiO polyhedral nanoparticles were obtained. Both the active hydrogen and nitrogen species generated in the NH3plasma were essential for a-SiOxNynanowire formation:  the former one kept the activity of the catalyst while the later one ensured efficient nitrogen incorporation. Two factors were found to be essential for nanowire growth:  the elemental state of Ni and sufficient active species in the gas phase. The Fourier transformed infrared (FT-IR) and Raman spectra of the obtained a-SiNxOynanowires were studied.