Performance analysis of a new metalhyphen;insulatorhyphen;semiconductor capacitor incorporated with Pthyphen;SnOxcatalytic layers for the detection of O2and CO gases

摘要

The integration of the catalytic properties of platinum (Pt) and tin oxide (SnOx) in the Pthyphen;SnOxhyphen;Si3N4hyphen;SiO2hyphen;Si metalhyphen;insulatorhyphen;semiconductor (MIS) capacitor allows the detection of oxygen (O2) and carbon monoxide (CO) gases at a much lower operating temperature than that of the conventional solidhyphen;state gas detectors. The operation characteristics of the device for the detection of O2and CO are described as a function of the gas pressure and temperature ranging from 27 to 100thinsp;deg;C. Repeatability of the device for CO detection in an open air ambient is also presented. A model based on adsorption/reaction of oxygen ions at the Pthyphen;SnOxinterface of the MIS capacitor is proposed for oxygen/carbon monoxide detection. The physical and chemical mechanisms responsible for the gas sensing behaviors are discussed. The detection mechanisms explain the device behaviors and account for the following experimental observations and reaction kinetic analysis of the experimental data: (1) the dependence of the reaction kinetics on the square root of the O2partial pressure, (2) the requirement of oxygen as a constituent of the background gas for CO detection, (3) the inverse proportional relationship of the reaction kinetics to CO partial pressure, and (4) the need of Pt and SnOxas the catalytic layers in the MIS capacitor for gas detection.