Humidity-Tolerant Ultrathin NiO Gas-Sensing Films
| Autor: | Alaric Taylor, Cristian E. Simion, Claire J. Carmalt, Christopher S. Blackman, Stefan Guldin, Adelina Stanoiu, James A. Covington, Rachel L. Wilson |
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| Rok vydání: | 2020 |
| Předmět: |
Materials science
Bioengineering 02 engineering and technology Chemical vapor deposition 01 natural sciences symbols.namesake Operating temperature QD Instrumentation Debye length Fluid Flow and Transfer Processes business.industry Process Chemistry and Technology 010401 analytical chemistry Non-blocking I/O Temperature Humidity 021001 nanoscience & nanotechnology 0104 chemical sciences Active layer Semiconductor Semiconductors symbols Optoelectronics Nanometre Gases 0210 nano-technology business |
| Zdroj: | ACS Sensors. 5:1389-1397 |
| ISSN: | 2379-3694 |
| DOI: | 10.1021/acssensors.0c00172 |
| Popis: | When the gas sensor active layer film thickness is decreased, increased sensitivity to changes in the adsorbate concentration is expected when measuring the resistance of the layer, in particular when this thickness is on the order of the Debye length of the material (one–tens of nanometers); however, this is demonstrated only for a limited number of materials. Herein, ultrathin NiO films of different thicknesses (8–21 nm) have been deposited via chemical vapor deposition to fabricate gas sensor devices. Sensor performance for a range of NO2 concentrations (800 part-per-billion to 7 part-per-million) was evaluated and an optimum operating temperature of 125 °C determined. The dependence of the potential relative changes with respect to the NO2 concentration and of the sensor signal with respect to the geometrical parameters was qualitatively evaluated to derive a transduction model capable of fitting the experimental results. The selective sensitivity toward NO2 was confirmed by the limited response for different reducing gases, CO, CH4, NH3, and SO2, under optimum operating conditions, and the sensor signal toward NO2 increased with decreasing thickness, demonstrating that the concept of a Debye length dependence of sensitivity is applicable for the p-type semiconductor NiO. In addition, these NiO sensors were exposed to different relative levels of humidity over a wide range of operating temperatures and were found to display humidity tolerance far superior to those in previous reports on SnO2 materials. |
| Databáze: | OpenAIRE |
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