Modulating The Stability And Optoelectronic Properties Of Inse And Bp Based On Interface Engineering

In recent years,the two-dimensional semiconductor materials have been favored by researchers due to its unique optical,electrical and other excellent performance.Application research based on two-dimensional semiconductors has also developed vigorously.They are the new-generation semiconductor materials most likely to replace silicon-based materials,and have huge potential in many fields such as memory,photodetectors,and biosensors.In the face of opportunities,two-dimensional semiconductor materials also face challenges such as large contact resistance of metals-semiconductors,difficulty in obtaining high responsiveness and fast response time for optoelectronic devices at the same time,and difficulty in ensuring long-term stable and efficient work.Among them,indium selenide（InSe）and black phosphorus（BP）,as representatives of unstable materials in the environment,which are expected to replace graphene due to their performance of narrow band gap,high mobility and fast light response time.However,a serious problem of environmental degradation greatly limits their practical application.Therefore,a deep understanding of the degradation processes of InSe and BP and the exploration of methods that can both enhance their stability and improve their electrical and optoelectronic properties are great significance for their application.This paper focuses on the materials of In Se and BP semiconductor,and discusses the above problems.The main research contents and conclusions are as follows.1.Modulating the thermal stability of InSe based on heterostructure of interface engineering.Firstly,the thermal stability of In Se in air was studied by means of continuous thermal annealing.The thermal oxidation process of In Se was decomposed into three stages:at low temperature（<200℃）,oxygen was adsorbed on the surface of In Se and p-type doping was carried out.At moderate temperature（200-450℃）,O atoms break In-Se bonds and form InSe1-xOx oxides by bonding with In and Se.At high temperature（>450℃）,Se atoms on the surface are completely replaced by O atoms,leaving the final oxidation product in the surface layer,In₂O₃,and In Se intact at the bottom layer.Secondly,based on the oxidation mechanism,we proposed and compared three heterogeneous structures that improve the thermal stability of InSe:MoTe2-In Se,graphene-InSe,and h-bn-In Se.Finally,it was found that the InSe covered by h-BN had the highest stability in the air,and it could be stabilized to 620℃.2.Modulating the optical and photoelectric performance of BP based on surface treatment of interface engineering.Firstly,we compared the stability of BP samples with different layers in the air,and found that samples with more than ten layers can be spontaneously stable for more than two weeks.Compared with the samples after mild oxygen plasma treatment,it was found that the main factors affecting the stability of BP was the compactness of the surface oxide layer.Secondly,mild oxygen plasma treatment has improved the photoelectric performance of BP（responsivity increased from 0.03 A/W to0.19 A/W）.Finally,we constructed the BP-MoS₂ heterojunction,which improved the stability of the BP device（two months in the air environment）,and enhanced the responsivity at 940nm wavelength（2 times higher than BP detector）.3.Modulating the optical and photoelectric performance regulation of BP based on metal-semiconductor contact of interface engineering.BP FET-type photodetectors of the same thickness were prepared by three methods:mask plate direct evaporation electrode method,transfer electrode method and electron beam exposure technique（EBL）.Combined with the theoretical analysis from contact method,hysteresis characteristics,and contact resistance of the three devices to explore the factors that affect the performance of the device.It was found that interface defects were important factors affecting electrical and optoelectronic performance.The interface is contaminated during the preparation process of the copper grid evaporation,so the interface has many defects,large hysteresis,and the shortest light response time,but the response is lower.On the contrary,the device interface prepared by EBL technology has less residual impurities,so the hysteresis is smaller,the light response time is the longest,but the response is higher.And the performance of the transfer electrode method is somewhere in between.