Functionalized individual ZnO microwire for natural gas detection

A single ZnO microwire detector for the monitoring of natural gas species is described. Single-crystal ZnO microwires were synthesized using a carbothermal reduction vapor phase transport method. It was characterized by XRD, EDX, SEM, Raman and photoluminescence techniques. The sensor structure was fabricated by in situ lift-out method using focused ion beam (FIB) system. The prototype is then functionalized with palladium and used as sensing element. The main advantage of the FIB procedure is a quick verification/testing of concept and is compatible with micro/nanoelectronic devices. A response of 5% was obtained for a single ZnO microwire sensor at 2000 ppm natural gas in the air at room temperature. At 400 °C the response increases to 40%. Selectivity to different gasses was investigated and higher response was detected for natural gas.