title: Enhanced room-temperature NO2gas sensing with TeO2/SnO2brush- and bead-like nanowire hybrid structures.
abstract: We have synthesized two highly sensitive, room-temperature operating TeO2/SnO2gas sensors with hierarchical nanowire structures. One is a brush-like nanostructure, from a two-step thermal vapor-transport route, and the other one is a TeO2/SnO2bead-like nanostructure, from annealing of the former. The TeO2/SnO2nanostructures exhibit a greatly enhanced room-temperature gas-sensing response compared to pristine TeO2nanowires in the sequence: TeO2/SnO2bead-like structure > brush-like structure > pristine TeO2nanowire. The response of the TeO2/SnO2bead-like structure is in a range of 10 to 20 against NO2gas of ppm levels (3-100 ppm) at room temperature. This compares favorably to the response, smaller than 2, for the pristine TeO2nanowires. Interestingly, the TeO2/SnO2bead-like structure exhibits a typical n-type gas-sensing behavior, in contrast to the p-type behavior from the brush-like and the pristine TeO2structures. Possible hybrid growth and sensing mechanisms are discussed.
authors.affiliation: Department of Materials Science and Engineering, National Chung Hsing University, Taiwan.
authors.forename: Bu-Yu
authors.initials: BY
authors.lastname: Yeh
authors.forename: Ping-Fu
authors.initials: PF
authors.lastname: Huang
authors.forename: Wenjea J
authors.initials: WJ
authors.lastname: Tseng