Structural, optical and sensing properties of pure and Cu-doped SnO2 nanowires.

In present work, pure and copper (Cu) doped SnO2 nanowires have been synthesized by thermal evaporation process at ambient pressure. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) indicated the growth of wire-like pure and Cu-doped SnO2 nanostructures with their length of about 50 microm and 80 microm whereas transverse dimension of about 50-80 nm and 20-50 nm, respectively. The HRTEM and SAED pattern reveals the growth of single crystalline Cu-doped SnO2 nanowire. The EDX confirms that Cu has been doped in the SnO2 nanowires and atomic fraction of Cu in nanowires is about 2.5 at% when concentration of CuO in starting source powder is 50 wt%. X-ray diffraction showed that Cu gets incorporated into the SnO2 lattice and also confirms their tetragonal rutile structure. For comparative study of gas sensing properties of pure and Cu-doped SnO2 nanowire, isolated single nanowire based sensors have been fabricated for detection of ethanol gas. The doping of Cu was found to enhance the ethanol sensitivity of SnO2 nanowire based sensors and the sensor response improves with increase in ethanol concentration. This sensing behaviour offers a suitable application of the Cu-doped SnO2 nanowire sensor for detection of ethanol gas.