Ultraviolet photodetectors made from SnO2 nanowires

SnO2 nanowires can be synthesized on alumina substrates and formed into an ultraviolet (UV) photodetector. The photoelectric current of the SnO2 nanowires exhibited a rapid photo-response as a UV lamp was switched on and off. The ratio of UV-exposed current to dark current has been investigated. The SnO2 nanowires were synthesized by a vapor-liquid-solid process at a temperature of 900 degrees C. It was found that the nanowires were around 70-100 nm in diameter and several hundred microns in length. High-resolution transmission electron microscopy (HRTEM) image indicated that the nanowires grew along the [200] axis as a single crystallinity. Cathodoluminescence (CL), thin-film X-ray diffractometry, and X-ray photoelectron spectroscopy (XPS) were used to characterize the as-synthesized nanowires. (C) 2009 Elsevier B.V. All rights reserved.