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Pure and Cu doped SnO2 nanowires and nanobelts were grown in a tubular furnace under argon atmosphere at ambient pressure. X-ray diffraction showed that Cu gets incorporated into the SnO2 lattice. Isolated single nanowire sensors have been fabricated for detection of H2S gas at room temperature. Cu doping was found to reduce the sensitivity of these sensors in contrast to results reported for Cu doped SnO2 thin films. Photoluminescence studies indicate that the reduction is sensitivity may be due to reduced defect density. [ABSTRACT FROM AUTHOR]

Hydrothermal growth of ZnO nanowires were performed using ZnO nanoparticles as a seed layer. The growth was found to depend strongly on the reaction duration. These nanowires detected H2S with faster response and recovery time of 13 and 78 s, respectively towards 20 ppm at 350° C. The lowest detection limit was improved to 0.6 ppm upon annealing in O2 flow of 50 sccm. The response time was further improved to just 6 s towards 20 ppm of H2S at 350° C. The enhanced response characteristics have been attributed to the high surface area to volume ratio of nanowires. Photoluminescence (PL) studies showed increase in the green emission related to defect states in ZnO. This is also expected to contribute for the improved sensing characteristics. [ABSTRACT FROM AUTHOR]