Selective synthesis of SiO2 NWs on Si substrate and their adjustable photoluminescence

Amorphous SiO2 nanowires with diameters of 20–200 nm and lengths of several micrometers were selectively grown，at 1100 °C under ambient pressure，on the ultra-thin Au film coated silicon wafers，which were characterized by scanning electron microscope, Fourier transform infrared spectroscope, and high resolution transmission electron microscope. Using X-ray energy dispersion spectroscope equipped on the high resolution transmission electron microscope, the investigation was carried out on the micro-region chemical composition of the as-grown amorphous SiO2 nanowire. The growth mechanism has been discussed, and it has been believed to be extended vapor-liquid-solid process. The SiO2 layer, as the result indicates, can prevent the formation of Si–Au alloy from Si–Au interface. This work also discusses the photoluminescence emission from SiOx centers at room temperature, it is found that by changing the oxygen, the photoluminescence intensity can be adjusted.