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Density-controllable growth of SnO2 nanowire junction-bridging across electrode for low-temperature NO2 gas detection
- Le, Dang Thi Thanh, Van Duy, Nguyen, Tan, Ha Minh, Trung, Do Dang, Trung, Nguyen Ngoc, Van, Phung Thi Hong, Hoa, Nguyen Duc, Van Hieu, Nguyen
- Journal of materials science 2013 v.48 no.20 pp. 7253-7259
- electrodes, ethanol, evaporation, hydrogen sulfide, nanowires, nitrogen dioxide, spatial distribution, temperature
- The junction-bridging structure of metal oxide nanowires (NWs) improves gas-sensing properties. In this study, an on-chip growth method was used to fabricate gas sensors, it easily and effectively controls NW junctions. SnO₂NWs were synthesized by thermal evaporation at 800 °C with tin powder as the source. The density of the NW junctions was controlled by changing the mass of the source material. A source material with large mass yielded high-density NW junctions. With electrode spacing of 20 μm, NW junctions were formed from the source material of larger than 2 mg. Gas sensing results revealed that the junction sensors exhibited a good response to NO₂gas at a concentration of 1–10 ppm. The sensors exhibited a good response to NO₂gas at low temperature of up to 100 °C and short response–recovery time (~20 s). The sensors also had good selectivity to NO₂gas. The response (Rgₐₛ/Rₐᵢᵣ) to 1 ppm NO₂was as high as 22 at 100 °C, whereas the cross gas responses (Rₐᵢᵣ/Rgₐₛ) to 10 ppm CO, 10 ppm H₂S, 100 ppm C₂H₅OH, and 100 ppm NH₃were negligible (1.1–1.3).