Synthesis And Electronic Transport Property Of Single-Crystalline Hexagonal Tungsten Trioxide Nanowires

One-dimensional (1D) semiconductor nanowires have been investigated extensively due to their unique chemical/physical properties and potential applications in optical information storage, single-electron transport devices, luminescence display and electronic sensors. So the synthesis and electronic transport property of semiconductor nanowires have been the focus of scientific research at present. In this paper, the main results and conclusions are summarized as following:In Chapter 2, hexagonal tungsten trioxide (WO3) nanowires were prepared by thermal evaporation of tungsten trioxide powder in a horizontal tube furnace. The morphology and structure of the products were characterized. The experimental conditions were studied. The formation mechanism of semiconductor nanowires was also investigated and analyzed in details.In Chapter 3, the individual WO3 nanowire was assembled by AC electric field with the proper voltage and frequency. In our electronic transport property measurements, the I–V characteristic of the WO3 nanowire assembled by this process displays a rectifying behavior in the dark. This I-V characteristic could be explained by two back-to-back Schottky barriers with different heights which can be attributed to the asymmetric contact between the WO3 nanowire and the Pt electrodes formed in the dielectrophoresis aligning process. Under UV illumination, the I-V characteristic of WO3 nanowire could be greatly changed which showed that the nano-metal/semiconductors (nano-M/SCs) had photo-electric switching effect.In Chapter 4, we groped to synthesize TiO2/WO3 nanowires, the results of characterition of our samples indicated that we just obtained WO3 nanowires without TiO2/WO3 nanowires using thermal evaporation of TiO2/WO3 Powder. We think that this was because TiO2 did not sublime at the undersurface of 2000℃.