Enhanced room-temperature NO₂gas sensing with TeO₂/SnO₂brush- and bead-like nanowire hybrid structures

Abstract

We have synthesized two highly sensitive, room-temperature operating TeO/SnO gas 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 TeO/SnO bead-like nanostructure, from annealing of the former. The TeO/SnO nanostructures exhibit a greatly enhanced room-temperature gas-sensing response compared to pristine TeO nanowires in the sequence: TeO/SnO bead-like structure > brush-like structure > pristine TeO nanowire. The response of the TeO/SnO bead-like structure is in a range of 10 to 20 against NO gas of ppm levels (3-100 ppm) at room temperature. This compares favorably to the response, smaller than 2, for the pristine TeO nanowires. Interestingly, the TeO/SnO bead-like structure exhibits a typical n-type gas-sensing behavior, in contrast to the p-type behavior from the brush-like and the pristine TeO structures. Possible hybrid growth and sensing mechanisms are discussed.

Template-Free Construction of Tin Oxide Porous Hollow Microspheres for Room-Temperature Gas Sensors

“…Therefore, when the concentration is 40 mg/mL, the sensor response is the highest. Compared with other NO 2 gas sensors (Table ), our SnO 2 PHM gas sensor demonstrates superior NO 2 sensing performance. ,− The SnO 2 PHM gas sensor exhibits excellent sensing performance characteristics because it provides a large inner reaction region, an easy gas diffusion pathway or channel, and large accessibility of material surfaces to target gas molecules. The structure of PHMs is expected to reduce the operating temperature and this may break through the bottleneck that hinders the realization of large-scale Internet of Things and artificial intelligence applications in semiconductor gas sensors.…”

Effect of heat treatment on surface structure and gas sensing of electrospun ZnO‐SnO2 composite nanofibers

“…125 µm between the neighboring finger electrodes. 21,22 The electrical resistance of the samples was recorded by a Keithley 6517B high-resistance electrometer. The atmosphere used was either synthetic dry air or NO 2 gas (balanced with the synthetic air) with concentrations ranging from 10 to 30 ppm.…”

“…The interdigitated electrode with an overall areal dimension of 8 × 11.5 mm 2 consisted of finger‐type electrodes with an electrode width of 300 µm and an interelectrode spacing of ca. 125 µm between the neighboring finger electrodes 21,22 . The electrical resistance of the samples was recorded by a Keithley 6517B high‐resistance electrometer.…”

Metal Oxide Based Heterojunctions for Gas Sensors: A Review

“…The Fermi level of ZnO is higher than that of Co3O4, inducing the transfer of Oxygen molecules are reported to be more easily adsorbed onto the surface of p-type metal oxides, which is another reason for the improved NO 2 gas sensing performance of the Co 3 O 4 -decorated ZnO nanoparticles. The improvements in the NO 2 gas sensing properties of the SnO-SnO 2 nanocomposites [90], CuO-decorated ZnO nanowires [155], TeO 2 /SnO 2 brush-nanowires [156] and ultra-long ZnO@Bi 2 O 3 heterojunction nanorods [157] can also be attributed to the reasons listed above.…”