High-yield fabrication of t-Se nanowires via hydrothermal method and their photoconductivity

Large-scale fabrication of high-purity and uniform trigonal selenium (t-Se) nanowires was obtained by reducing SeO₂ with glucose at 160 °C for 24 h. The resulting t-Se nanowires were characterized and confirmed by means of an X-ray diffractometer, scanning electron microscope, transmission electron microscope and energy dispersive X-ray spectroscope. The results indicated that the high yield uniform t-Se nanowires have high degree of crystallinity. The selected area electron diffraction pattern and high-resolution transmission electron microscopy image demonstrate perfect crystallinity with the growth direction of [001]. Owning to quantum size effect, a significant blue shift could be identified in the absorbance spectroscopy of as-prepared products. The photoconductivity of t-Se nanowires with light was also investigated and reached maximum at the wavelength of 575 nm, which might be useful in the fabrication of micro-devices or photo-switches. Contrast experiments showed that surfactant Tween-40 played a crucial role in the formation of nanowires.