Modulation of Agglomeration of Vertical Porous Silicon Nanowires and the Effect on Gas‐Sensing Response |
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Authors: | Yuxiang Qin Yunqing Jiang Liming Zhao |
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Affiliation: | 1. Tianjin Key Laboratory of Imaging and Sensing Microelectronic Technology, Tianjin University, Tianjin 300072, China;2. Key Laboratory for Advanced Ceramics and Machining Technology, Ministry of Education, School of Materials Science and Engineering, Tianjin University, Tianjin 300072, China;3. School of Microelectronics, Tianjin University, Tianjin 300072, China |
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Abstract: | Porous silicon nanowires (PSiNWs) array is a promising material for development of integrated gas sensors operating at room temperature. This work reports the fabrication of PSiNWs assembly with different structural features and its effect on gas‐sensing performance. Bundling and well separating PSiNWs arrays are fabricated by MACE method, respectively, based on the effective modulation of surface wettability of the initial Si substrate. The HF pretreatment creates a hydrophobic surface favorable for deposition of irregular Ag nanoflakes and then for the formation of bundling PSiNWs array. In contrast, the PSiNWs with well lateral separation are formed based on the predeposited uniform Ag nanoparticles on a hydrophilic Si surface. The PSiNWs array featured by tip‐clusters is proved to be highly effective in achieving highly sensitive and rapid response to NO2 gas at room temperature. Satisfying dynamic characteristic and selectivity are meanwhile observed for the bundling array. The formation of the bundling or separating of PSiNWs is discussed in terms of the force balance of individual nanowire, which is further correlated with non‐uniform distribution of Ag nanoclusters caused by H‐termination. Meanwhile, high sensing performance of bundling nanowires is analyzed based on the structural promotion of the unique configuration of tip‐cluster to sensing response. |
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Keywords: | Modulation of wettability NO2 detection Porous silicon nanowires Tip‐cluster |
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