Study On Fabrication And Diethyl Ether Sensing Properties Of ZnO Based Gas Sensor Modified By Mg²⁺ Ion

In recent years, security issues caused by diethyl ether?DEE? have gained much more attention due to its applications in chemical factories, chemical laboratories and hospitals and its toxicity, strong volatility, inflammability and explosive risk. Metal oxide semiconductor gas sensors have been widely used in detection of different kinds of toxic, flammable and explosive gas/odor because of high sensitivity, low cost, convenient operation, simple structure, easy fabrication and other excellent characteristics. In this article, ZnO was employed as the base sensing material, which was then modified using surface micro injection method to research their DEE vapor sensing properties. As is known, diethyl ether is a kind of organic compound with reducibility. So this study aimed to fabricate the appropriate gas sensors to detect and identify the diethyl ether vapor, and explore the underlying chemical reactions and the characteristics of the DEE vapor sensing reactions, thus laying the foundation for the fabrication of high-performance DEE sensor device.In this work,ZnO was prepared by homogeneous precipitation method and modified through surface micro injection of six kinds of metal ion chloride solutions, i.e. CuCl2, MgCl2, FeCl3, AlCl3, TiCl4 and SnCl4 aqueous solutions. The research results indicated that the sensitivity of ZnO sensing layer towards the diethyl ether vapor exhibit a certain improvement after surface doping of six metal ions, among which the Mg²⁺ surface doping had the best sensitization effect on ZnO sensing layer. In particular, Mg²⁺ surface modified ZnO thick film sensor with an injection amount of MgCl2 at 10×10-3 ?mol exhibited the highest response value of 23 towards 200 ppm of DEE vapor.Then the homogeneous precipitation method for ZnO preparation was optimized and bulk doped Mg-ZnO structure was prepared by this chemical precipitation reaction. The diethyl ether vapor sensing performance test was also conducted, further revealing the remarkable sensitization effect of Mg²⁺ on ZnO matrix. And the parameters such as sensitivity, response time and optimal working temperature were extracted and researched. It was found that higher sensitivity, shorter response time and lower optimal working temperature were realized after Mg²⁺ bulk doping. Through the curve fitting of the relationship between sensitivity and diethyl ether vapor concentration, the gas sensing mechanism of bulk doped Mg-ZnO was analyzed. Afterwards, a simple comparison between the diethyl ether sensing mechanisms of both Mg-ZnO systems prepared by two different modification methods was conducted, further revealing the diethyl ether sensing mechanism of Mg²⁺ doped ZnO sensing material.