程序降温下金属氧化物表面存在化学吸附氧累积，可将气体敏感性提高100倍左右
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作者:whhcrk
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发布时间: 2016-09-08
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3412 次浏览
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Metal oxide used as resistive gas sensor has been known for a long time and the resistance variation isrelated to the gas around sensor. This behavior can be rationalized by the model of oxygen ionization,which has relation to the oxygen adsorption. One special phenomenon that the irreversible R-T curvesof metal oxide gas sensor under programmed temperature cycle appears repeatedly in previous reports.However the classical adsorption isobar cannot explain it perfectly. Herein a series of experiments weredesigned to reveal the laws of the irreversible R-T curves. Moreover the proper adsorption potentialenergy curves and the adsorption isobar for oxygen adsorption were proposed to better illustrate themechanisms. Based on the above theory, we found a way to obtain the surface state filled with abundantchemisorbed oxygen. For pure SnO2, it can maintain at least 27 min within the 5% decrease of resistance.Simultaneously the gas sensing behavior was investigated at room temperature. It will contribute to more thoroughly understand the characteristic of metal oxide gas sensor.
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