The Sensing Performance Regulation Of Metal Sulfide Semiconductor-based NO₂ Gas Sensor By Decorating Graphene

With the advent of 5G,we have entered the era of intelligent sensor of Internet of everything.As the window and medium to obtain external information,sensor is the core part of the whole 5G application network.As one of the sensors,gas sensor has a wide range of applications and has a great market prospect.Semiconductor metal oxides account for a large part of today's sensor market and are widely studied.However,the metal oxide based sensor still faces some limitations,such as poor selectivity,high operating temperature and poor stability.The reason for the poor stability is the existence of oxygen vacancies in metal oxides,which lack thermodynamic equilibrium with the external environment,thus causing the change of mobility.Since the presence of sulfur vacancy rather than oxygen vacancy in the metal sulfide,there is no process of interaction with the external ocean,and the stability will be improved to some extent.Metal sulfides are cheap and can be synthesized by hydrothermal,atomic deposition,chemical vapor deposition,etc.In addition,metal sulfide has adjustable energy band structure,good affinity and electrochemical properties.Therefore,this paper takes metal sulfide as the core,regulates its gas sensitivity through composite graphene,and develops a gas sensor with high performance and fast real-time monitoring for the market.The main work contents are as follows:1.we used 2D SnS₂ as main material and regulated microstructure,particle aggregation,chemical state and gas sensitive properties by adjusting the addition amount of graphene.We found that when the addition amount of graphene was 0.8%,gas sensor achieved the best performance,the reason of which is the synergy of geometric effect,chemistry effect and electron effect.2.We took three-dimensional zinc sulfide sphere as the main material and adopted the same method to regulate the microstructure,chemical state and gas-sensitive properties of zinc sulfide by changing the addition amount of graphene.We found that when the addition amount of graphene was 0.5%,the gas-sensitive properties of the sensor reached the best.However,compared with the significant effect brought by the introduction of graphene in chapter 2,the improvement of zinc-based gas sensor by the introduction of graphene was not obvious,which was caused by the relative limitations of 2D/3D composite structure.This paper focuses on the commercialization trend of 5G and discusses the regulation effect of graphene on the gas sensitivity of metal sulfide in detail based on metal sulfide based gas sensor.By comparing 2D/2D SnS₂/graphene materials with2D/3D zinc sulfide/graphene composites,the effects of different semiconductor contact types on gas sensitivity were summarized.The experimental conclusion and analytical method can be used for reference for researchers of sulfide based gas sensor.