Maier Konrad, Helwig Andreas, Müller Gerhard, Hille Pascal, Eickhoff Martin
Airbus Group Innovations, München D-81663, Germany.
Fachbereich 06, Munich University of Applied Sciences, Lothstraße 34, Munich D-80335, Germany.
Materials (Basel). 2015 Sep 23;8(9):6570-6588. doi: 10.3390/ma8095323.
In this work the low temperature response of metal oxide semiconductor gas sensors is analyzed. Important characteristics of this low-temperature response are a pronounced selectivity to acid- and base-forming gases and a large disparity of response and recovery time constants which often leads to an integrator-type of gas response. We show that this kind of sensor performance is related to the trend of semiconductor gas sensors to adsorb water vapor in multi-layer form and that this ability is sensitively influenced by the surface morphology. In particular we show that surface roughness in the nanometer range enhances desorption of water from multi-layer adsorbates, enabling them to respond more swiftly to changes in the ambient humidity. Further experiments reveal that reactive gases, such as NO₂ and NH₃, which are easily absorbed in the water adsorbate layers, are more easily exchanged across the liquid/air interface when the humidity in the ambient air is high.
在这项工作中，对金属氧化物半导体气体传感器的低温响应进行了分析。这种低温响应的重要特性是对形成酸和碱的气体具有显著的选择性，以及响应和恢复时间常数的巨大差异，这常常导致积分器类型的气体响应。我们表明，这种传感器性能与半导体气体传感器以多层形式吸附水蒸气的趋势有关，并且这种能力受到表面形态的敏感影响。特别是，我们表明纳米范围内的表面粗糙度增强了多层吸附物中水的解吸，使它们能够对环境湿度的变化做出更迅速的响应。进一步的实验表明，当环境空气中的湿度较高时，容易被水吸附层吸收的活性气体，如二氧化氮和氨气，更容易在液/气界面上进行交换。
