SnO₂ is one of the most employed n-type semiconducting metal oxide in chemo-resistive gas-sensing although it presents serious limitations due to a low selectivity. Herein, the authors introduce 1D SnO₂-SiO₂ core-shell nanowires (CSNWs). The amorphous SiO₂-shell layer with varying thicknesses (1.8–10.5 nm) is grown onto the SnO₂ nanowires (NWs) by atomic layer deposition (ALD). SiO₂-coated SnO₂ CSNWs show a dramatic improvement of the selectivity towards hydrogen. Moreover, the sensing-response is strongly correlated to the thickness of the SiO₂-shell and the working temperature. The SnO₂-SiO₂ CSNWs sensor with a 4.8-nm SiO₂ shell thickness exhibits the best selectivity and sensitivity, having ca. 7-fold higher response toward hydrogen compared to bare-SnO₂ NWs. The selectivity and enhanced sensing-response are related to the masking effect of the SiO₂ shell and an increase in the width of the electron-depletion-layer due to a strong electronic coupling between the SnO₂ core and SiO₂ coating, respectively.

中文翻译：

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用于选择性氢传感的 SnO2-SiO2 1D 核壳纳米线异质结构

SnO ₂是化学电阻气敏中最常用的n型半导体金属氧化物之一，尽管它由于低选择性而存在严重的局限性。在此，作者介绍了 1D SnO ₂ -SiO ₂核壳纳米线 (CSNW)。通过原子层沉积 (ALD) 将具有不同厚度 (1.8-10.5 nm)的非晶 SiO ₂壳层生长到 SnO ₂纳米线 (NW) 上。SiO ₂涂覆的SnO ₂ CSNW 显示出对氢的选择性的显着改善。此外，传感响应与SiO ₂壳的厚度和工作温度密切相关。SnO ₂-SiO ₂ CSNWs 传感器具有 4.8-nm SiO ₂壳厚度，表现出最佳的选择性和灵敏度，大约为 与裸 SnO ₂ NW相比，对氢的响应高 7 倍。由于SnO ₂核和SiO ₂涂层之间的强电子耦合，选择性和增强的传感响应分别与SiO ₂壳的掩蔽效应和电子耗尽层宽度的增加有关。