Micro humidity sensors based on ZnO-In₂O₃ thin films with high performances

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• 作者：Qingcheng Liang^a ; ^{liangqc2010@sina.com}  ; [Author Vitae] ; Hongliang Xu^b  ; [Author Vitae] ; Jianxun Zhao^a  ; [Author Vitae] ; Shang Gao^a  ; [Author Vitae]
• 关键词：ZnO ; In2O3 ; Micro sensors ; Metal oxide semiconductors ; Radio-frequency sputtering
• 刊名：Sensors and Actuators B ; Chemical
• 出版年：2012
• 期刊代码：161_09254005
• 类别：et
• 出版时间：April, 2012
• 卷：165
• 期：1
• 页码：76-81
• 文件大小：1070 K

摘要

Micro humidity sensors are fabricated by radio-frequency sputtering ZnO and In₂O₃ thin films on SiO₂/Si substrates with interdigitated Pt signal electrodes. By adjusting the sensing film form, the micro sensors with a tiny area (1.36 mm 脳 0.55 mm) exhibit controllable humidity sensing properties. The best sample is obtained by sputtering two times of ZnO and one time of In₂O₃ on sensor active area (0.63 mm 脳 0.55 mm). The corresponding impedance changes by more than four orders of magnitude over the whole testing humidity range (from 11%to 95%relative humidity), and the response and recovery times are about 15 s and 40 s, respectively. High stability and good consistency are also observed based on the as-fabricated sensors. The improved and excellent humidity sensing properties are explained by the hetero junctions between ZnO and In₂O₃ thin films. High sensor performance and large-scale fabricating potentiality demonstrate that the micro humidity sensors are very promising devices for humidity detection which could be produced at industrial level.