Improvement of gas selectivity, especially among volatile organic compound (VOC) gases, was attempted by introducing pulse-driven modes in semiconductor gas sensors. The SnO₂ microsensor was fabricated on a miniature sensor device constructed with a microheater and electrode. The gas-sensing properties were evaluated under a pulse-driven mode by switching the heater on and off. According to density functional theory calculations and temperature-programmed reaction measurements, toluene molecule, which is one of the VOC gases, was adsorbed on the SnO₂ surface by van der Waals forces. The conventional sensor response, S_e, defined as the change in the electrical resistance in air and target gas atmosphere, to toluene was four and eight times greater than that to CO and H₂, respectively. Moreover, the newly proposed sensor response, S_p, defined as the change in the electrical resistance of the device in the target gas atmosphere during the heater-on period, to toluene was 33 and 29 times greater than that to CO and H₂, respectively. This significant difference in the S_p to toluene was caused by the combustion reaction of condensed toluene within the sensing layer. Accordingly, the pulse-driven mode of the semiconductor gas sensor can be exploited to improve the gas selectivity of VOC gases based on these newly defined sensor response measures.

中文翻译：

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使用脉冲驱动的SnO ₂微型气体传感器选择性检测甲苯

通过在半导体气体传感器中引入脉冲驱动模式，试图提高气体选择性，特别是在挥发性有机化合物（VOC）气体中。SnO ₂微型传感器制造在由微型加热器和电极构成的微型传感器装置上。通过打开和关闭加热器，在脉冲驱动模式下评估气敏特性。根据密度泛函理论计算和程序升温反应测量，作为一种VOC气体的甲苯分子通过范德华力吸附在SnO ₂表面上。常规传感器响应，S _e甲苯（定义为空气和目标气体气氛中的电阻变化）分别是甲苯和CO和H _2的四倍和八倍。此外，新提出的传感器响应S _p定义为在加热器开启期间目标气体气氛中设备的电阻变化，它对甲苯的响应比对CO和H _2的响应分别大33倍和29倍。分别。S _p的显着差异甲苯的产生是由于传感层内缩合甲苯的燃烧反应引起的。因此，基于这些新定义的传感器响应措施，可以利用半导体气体传感器的脉冲驱动模式来改善VOC气体的气体选择性。