Kneer J, Eberhardt A, Walden P, Ortiz Pérez A, Wöllenstein J, Palzer S
Department of Microsystems Engineering - IMTEK, Laboratory for Gas Sensors, University of Freiburg, Georges-Köhler-Allee 102, 79110 Freiburg, Germany.
Rev Sci Instrum. 2014 May;85(5):055006. doi: 10.1063/1.4878717.
The use of semiconducting metal-oxide (MOX) based gas sensors in demanding applications such as climate and environmental research as well as industrial applications is currently hindered by their poor reproducibility, selectivity, and sensitivity. This is mainly due to the sensing mechanism which relies on the change of conductivity of the metal-oxide layer. To be of use for advanced applications metal-oxide (MOX) gas sensors need to be carefully prepared and characterized in laboratory environments prior to deployment. This paper describes the working principle, design, and use of a new apparatus that can emulate real-world conditions in the laboratory and characterize the MOX gas sensor signal in tailor-made atmospheres. In particular, this includes the control of trace gas concentrations and the control of oxygen and humidity levels which are important for the surface chemistry of metal-oxide based sensors. Furthermore, the sensor temperature can be precisely controlled, which is a key parameter of semiconducting, sensitive layers, and their response to particular gas compositions. The setup also allows to determine the power consumption of each device individually which may be used for performance benchmarking or monitoring changes of the temperature of the gas composition. Both, the working principle and the capabilities of the gas measurement chamber are presented in this paper employing tin dioxide (SnO2) based micro sensors as exemplary devices.
基于半导体金属氧化物（MOX）的气体传感器在气候与环境研究以及工业应用等苛刻应用中的使用，目前受到其可重复性差、选择性差和灵敏度低的阻碍。这主要归因于其传感机制依赖于金属氧化物层电导率的变化。为了用于先进应用，金属氧化物（MOX）气体传感器在部署前需要在实验室环境中进行精心制备和表征。本文描述了一种新装置的工作原理、设计和用途，该装置能够在实验室中模拟真实世界条件，并在定制的气氛中表征MOX气体传感器信号。特别是，这包括对痕量气体浓度的控制以及对氧气和湿度水平的控制，这对于基于金属氧化物的传感器的表面化学很重要。此外，传感器温度可以精确控制，这是半导体敏感层及其对特定气体成分响应的关键参数。该装置还允许单独确定每个设备的功耗，这可用于性能基准测试或监测气体成分温度的变化。本文以基于二氧化锡（SnO2）的微传感器作为示例设备，介绍了气体测量室的工作原理和功能。
