ZnO Nanowires As H2S Sensor.

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]