纳米棒
材料科学
热液循环
扫描电子显微镜
六角相
光谱学
半导体
氧化剂
分析化学(期刊)
能量色散X射线光谱学
六方晶系
化学工程
纳米技术
结晶学
光电子学
化学
复合材料
工程类
色谱法
物理
量子力学
有机化学
作者
Yuting Wu,Ming Hu,Xiaoying Wei
出处
期刊:Chinese Physics B
[IOP Publishing]
日期:2014-04-01
卷期号:23 (4): 040704-040704
被引量:18
标识
DOI:10.1088/1674-1056/23/4/040704
摘要
Hexagonal WO3 nanorods are fabricated by a facile hydrothermal process at 180 °C using sodium tungstate and sodium chloride as starting materials. The morphology, structure, and composition of the prepared nanorods are studied by scanning electron microscopy, X-ray diffraction spectroscopy, and energy dispersive spectroscopy. It is found that the agglomeration of the nanorods is strongly dependent on the PH value of the reaction solution. Uniform and isolated WO3 nanorods with diameters ranging from 100 nm–150 nm and lengths up to several micrometers are obtained at PH = 2.5 and the nanorods are identified as being hexagonal in phase structure. The sensing characteristics of the WO3 nanorod sensor are obtained by measuring the dynamic response to NO2 with concentrations in the range 0.5 ppm–5 ppm and at working temperatures in the range 25 °C–250 °C. The obtained WO3 nanorods sensors are found to exhibit opposite sensing behaviors, depending on the working temperature. When being exposed to oxidizing NO2 gas, the WO3 nanorod sensor behaves as an n-type semiconductor as expected when the working temperature is higher than 50 °C, whereas, it behaves as a p-type semiconductor below 50 °C. The origin of the n- to p-type transition is correlated with the formation of an inversion layer at the surface of the WO3 nanorod at room temperature. This finding is useful for making new room temperature NO2 sensors based on hexagonal WO3 nanorods.
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