One step fabrication of low noise CuO nanowire-bridge gas sensor

We report a new method to fabricate the CuO nanowire-bridge device operating one step thermal treatment and implementing as gas sensor. The X-ray Diffraction (XRD), micro Raman, and high resolution transmission electron microscopy measurements indicated that the CuO nanowires are single crystalline with high crystal quality. Both gas sensor performance and electrical properties of the nanowires-bridges are also investigated. The sensitivity of CuO nanowire-bridge device for sensing oxygen molecule is about 2 times higher than that of the CuO thin film device in room temperature. The enhanced sensitivity of the nanobridges can be attributed to the higher surface band bending due to the larger potential barrier as the accumulation layer between nanowire/nanowire junctions. The mechanism of sensing and electron transport are also discussed. Furthermore, the electrical noise property of the CuO nanowire-bridge device followed Hooge's 1/f-type fluctuations model, which suggests a high reliability of the gas-sensing device. This straightforward method of growing CuO nanowire bridging provides a new type of gas/bio sensing device to enhance sensing capability.