Dendritic composite array of silicon nanowires/WO^sub 3^ nanowires for sensitive detection of NO^sub 2^ at room temperature

• Published in: Materials letters Vol. 207; p. 29
• Main Authors: Qin, Yuxiang, Wang, Zefeng, Liu, Diao, Wang, Kehang
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier BV 15.11.2017
• Subjects: Chemical etching; Gas sensors; Materials science; Nanocomposites; Nanowires; Nitrogen dioxide; Response time; Room temperature; Selectivity; Sensors; Silicon; Studies; Tungsten oxides
• ISSN: 0167-577X

Dendritic composite array of silicon nanowires (SiNWs)/WO3 nanowires was prepared for highly sensitive gas sensor application. WO3 nanowires were grown directly on the top section of SINWs fabricated by metal-assisted chemical etching (MACE), through thermal annealing of pre-deposited W film to obtain dendritic SiNWs/WO3 nanowires array. At room temperature (RT), the composite sensor shows obviously enhanced sensing response to NO2 in comparison to pure SINWs sensor. The response value upon 5 ppm NO2 exposure is more than four folds of that from SiNWs. Meanwhile, good selectivity as well as perfect dynamic characteristic, especially ultrafast response (response time <1 s to 0.5-5 ppm NO2) is achieved for the composite sensor. The underlying sensing mechanism of the composite sensor is analyzed in detail.