Ethanol sensing properties and dominant sensing mechanism of NiO-decorated SnO2 nanorod sensors

• Published in: Electronic materials letters Vol. 13; no. 3; pp. 260 - 269
• Main Authors: Sun, Gun-Joo, Lee, Jae Kyung, Lee, Wan In, Dwivedi, Ram Prakash, Lee, Chongmu, Ko, Taegyung
• Format: Journal Article
• Language: English
• Published: Seoul The Korean Institute of Metals and Materials 01.05.2017; Springer Nature B.V; 대한금속·재료학회
• Subjects: Benzene; Carrier transport; Characterization and Evaluation of Materials; Chemistry and Materials Science; Condensed Matter Physics; Current voltage characteristics; Decoration; Depletion; Ethanol; Gas sensors; Materials Science; Nanoparticles; Nanorods; Nanotechnology; Nanotechnology and Microengineering; Nickel oxides; Optical and Electronic Materials; Potential barriers; Selectivity; Sensors; Tin dioxide; Toluene; VOCs; Volatile organic compounds; 전자/정보통신공학; junction; gas sensor; sensing mechanism; -; heterostructure; ethanol
• ISSN: 1738-8090; 2093-6788
• DOI: 10.1007/s13391-017-1719-6

NiO-decorated SnO 2 nanorods were synthesized by the thermal evaporation of Sn powders followed by the solvothermal deposition of NiO. A multi-networked p - n heterostructured nanorod sensor was fabricated by dropping the p -NiO-decorated n -SnO 2 nanorods onto the interdigited electrode pattern and then annealing. The multi-networked p - n heterostructured nanorod sensor exhibited enhanced response to ethanol compared with the pristine SnO 2 nanorod and NiO nanoparticle sensors. The former also exhibited a shorter sensing time for ethanol. Both sensors exhibited selectivity for ethanol over other volatile organic compounds (VOCs) such as HCHO, methanol, benzene and toluene and the decorated sensor exhibited superior selectivity to the other two sensors. In addition, the dominant sensing mechanism is discussed in detail by comparing the sensing properties and current-voltage characteristics of a p -NiO/ n -SnO 2 heterostructured nanorod sensor with those of a pristine SnO 2 nanorod sensor and a pristine NiO nanoparticle sensor. Of the two competing electronic mechanisms: a potential barrier-controlled carrier transport mechanism at a NiO-SnO 2 p - n junction and a surface-depletio n -controlled carrier transport mechanism, the former has some contribution to the enhanced gas sensing performance of the p - n heterostructured nanorod sensor, however, its contribution is not as significant as that of the latter.