Self-doped nanocolumnar vanadium oxides thin films for highly selective NO2 gas sensing at low temperature
| Autor: | Chong Yun Kang, Hi Gyu Moon, Soo Deok Han, Sahn Nahm, Myoung Sub Noh, Kwang Soo Yoo, Jung Joon Pyeon, Young Seok Shim, Jin Sang Kim |
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| Rok vydání: | 2017 |
| Předmět: |
Annealing (metallurgy)
Oxide Vanadium chemistry.chemical_element Nanotechnology 02 engineering and technology 010402 general chemistry 01 natural sciences chemistry.chemical_compound Adsorption Depletion region Materials Chemistry Electrical and Electronic Engineering Thin film Instrumentation Dopant Chemistry Doping Metals and Alloys 021001 nanoscience & nanotechnology Condensed Matter Physics 0104 chemical sciences Surfaces Coatings and Films Electronic Optical and Magnetic Materials Chemical engineering 0210 nano-technology |
| Zdroj: | Sensors and Actuators B: Chemical. 241:40-47 |
| ISSN: | 0925-4005 |
| DOI: | 10.1016/j.snb.2016.10.029 |
| Popis: | Vanadium dioxide (VO 2 ) as strong correlated oxide has been intensively studied due to the unique properties accompanied by metal-insulator transition (MIT) near room temperature. Their extrinsic electrical and optical transformations on MIT have been greatly attracted in many potential applications. In this study, we propose to apply an intrinsic electrical property of VO 2 in metallic phase as doping agent of chemiresistive sensor. Self-doped nanocoulmnar vanadium oxides (SNVO) thin films are simply fabricated by glancing angle deposition without any template and chemical additives. The nanocolumnar VO 2 thin films were deposited by e-beam evaporator, and then the SNVO with residual VO 2 in V 2 O 5 nanocolums were synthesized by an air atmosphere annealing, which are composed of dominant oxidized V 2 O 5 which plays a sensing role on the surface and the residual VO 2 with self-doping effect inside nanocolumns. Especially at low temperature (150 °C), SNVO sensor shows an ultra-high performance (R gas /R air > 100) to NO 2 (5 ppm) gas. It is supposed that the residual VO 2 which shows metallic properties above Mott transition temperature (∼67 °C) acts as an intrinsic electron donor by pseudo-free electron, which helps adsorption of oxygen ions on the surface and extends the depletion region of few nanometers of narrow necks between nanocolumns. |
| Databáze: | OpenAIRE |
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