In this paper, a new diffusion-reaction equation was formulated to research the influences of grain radius on the transients of gas transport and gas sensitivity for porous thin film medium semiconducting metal oxide gas sensor, based on the phenomenon that a target gas diffuses in the sensing film via Knudsen diffusion and reacts with adsorbed oxygen on the pore surfaces following Langmuir adsorption. In order to describe gas transport inside the sensing film, the equation has been solved numerically under unsteady-state conditions. When the gas concentration reached a steady state, the relationship between gas concentration and film depth was formulated using data fitting method to investigate the influences of grain radius on gas sensitivity, according to the linear relation between the sheet conductance of the sensing film and the gas concentration at the corresponding depth, and the reality that the conductance of the entire film is an integration of sheet conductance over the whole range of the film from the surface to the substrate.

中文翻译：

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多孔薄膜半导体金属氧化物气体传感器灵敏度的晶粒半径相关性研究

在本文中，基于目标气体在多孔薄膜介质半导体金属氧化物气体传感器中扩散的现象，建立了一个新的扩散反应方程来研究颗粒半径对气体传输瞬态和气体灵敏度的影响。传感膜通过 Knudsen 扩散并在朗缪尔吸附后与孔表面上吸附的氧气反应。为了描述传感膜内的气体传输，在非稳态条件下对方程进行了数值求解。当气体浓度达到稳态时，采用数据拟合的方法建立气体浓度与膜层深度的关系，研究颗粒半径对气体敏感性的影响，