金属氧化物半导体是研究最多与应用最广泛的气敏元件类型之一，其存在最主要的缺陷是选择性差。目前，可控调节测试条件中的气体浓度或工作温度，可获取元件瞬态电导信号，增强金属氧化物气敏元件的选择性，但调节气体浓度方式受气体类别与测试腔结构一致性限制；温度调制方式存在器件结构复杂、温度难准确控制、成本高等缺陷。本课题拟采用光通断调制方式获取金属氧化物气敏的瞬态电导信号，不仅可克服上述缺陷，由于光生载流子可改变表面活性中心数量，以及光对不同类别气体存在不同的最佳活化波长，光通断调制方式在增强金属氧化物气敏元件选择性上可具有更优的性能。本课题的开展，对于金属氧化物的气体光电响应机制，以及金属氧化物气敏元件选择性调控机制等研究有着重要的科学意义；对金属氧化物气敏元件及元件阵列在煤矿安全、空气质量等在线检测应用中的推广有着重要的实用意义。

Metal oxide gas sensor is widely used in many applications. One serious problem of metal oxide is the poor selectivity. To modulate gas concentration or working temperature in measuring process, the dynamic response of metal oxide could be gotten. And the selectivity could be improved by the dynamic response. However, gas concentration modulation is limited by the sample sort and the structure unity of testing chamber; temperature modulation has defects of device structure complexity, difficulty in temperature precisely control, and high cost. In this proposal, light on-off modualtion is used to get dynamic reponse. The light on-off modulation does not have the above defects of gas concentration or working temperature modulation. In addition, the selectivity of metal oxide could be higher improved by light on-off modulation with the reasons that: it has different activation light wavelengths towards different sorts of gas. The research in light on-off modulation, could help the understanding of the mechanism of gas-light response of metal oxide, and accelerate the application of metal oxide gas sensor and sensor array in air quality detection and mine safety monitoring.