Single metal oxide nanowire devices for ammonia and other gases detection in humid atmosphere

摘要

Metal oxide nanowires have been deposited on 100 nm SiO_2/Si substrates and SnO_2 and ZnO single nanowire devices have been fabricated by electron beam lithography technique. Gas sensing tests have been carried out, in order to detect ammonia, CO and NO_2 under standard humidity conditions. The devices have been also tested in either dark condition or exposed to ultraviolet light at room temperature. SnO_2 nanowires are able to detect ammonia at concentration of the order of few ppm also in dark conditions, they are sensitive to NO_2 and cannot detect CO. ZnO devices show good sensitivity to 5 ppm of ammonia in 30% relative humidity atmosphere. The samples have been mounted on a TO-39 case in a field effect transistor configuration in order to study the influence of the back-gate voltage on the single nanowire devices gas sensing performances.