Theoretical Investigation Of GaAs Monolayer Properties And Design A Nobel Monolayer

The exploration of two-dimensional?2D?monolayer materials have received considerable attentions owing to their unique electronic,magnetic,and optical properties.During the past decades dozens of excellent 2D monolayer materials such as graphene,2D oxides,and 2D chalcogenide structure etc.have been found and designed.However,the research on 2D materials with outstanding property needs to further study and developing.Among these materials the 2D monolayers with III–V elements have considered as leading members for potential applications.In recent years,there have been intensive research efforts regarding structural and electronic property of 2D monolayer of III–V elements.Although,III–V 2D monolayer materials are intensively explored,reports on investigation of GaAs monolayer are relatively scarce.The crystal structure of GaAs monolayer belongs to R3m non-centrosymmetric structure,and the structure could produce SHG response;nevertheless,SHG response of GaAs monolayers quite rare.Therefore,this study further explores the monolayer NLO properties and vacancy regulation of GaAs.Furthermore,the photocatalytic activity of GaAs monolayer was studied on the basis of the visible light region band gap,the large transfer rate and large carrier mobility of the parents,and the large absorption area of the monolayers.Theoretical design of crystal structure is an important way to expand single-layer species.At present,some progress and achievements have been made in relevant research.Among them,the theoretical design of nonlinear optical monolayer crystals is not uncommon.At present,the common disadvantage of nonlinear monolayer is that the band gap is small and can not be used in ultraviolet light region,so the theoretical design of large band gap nonlinear optical single layer has attracted much attention.In this paper,a monolayer of large band gap nonlinear optics is designed by means of the first principle calculation.The main research works and results are shown as follow:1.SHG effects and vacancy effects to GaAs monolayer properties:In this work,the nonlinear optical properties of GaAs monolayer are studied by means of the first principle calculation,and the effects of different vacancies on the properties like crystal structure,electricity,magnetism and optics properties of GaAs monolayers are studied.The results show that the single layer of GaAs has a strong nonlinear optical properties,and the effects of different vacancies on the crystal structure,electricity,magnetism,optics and other properties of GaAs single layer are obvious.2.Simulation study fore monolayer photocatalytic properties:There,with the aim of seeking efficient photocatalytic material,we investigated the photocatalytic activity of GaAs monolayer by first principle calculation.According to the obtained appropriate band gap,pressure sensitive band edge,strong absorption in visible light,and exothermic water absorption,we concluded that the GaAs monolayer is promising photocatalytic water splitting material.In addition,the monolayer GaAs has a large anisotropic carrier mobility,which is helpful to reduce the photosynthetic carrier compound rate and improve the photocatalytic efficiency.3.Newly designed monolayer:Under the structure frame of classical nonlinear optical crystal KBe₂BO₃F₂,a new monolayer Be₂CO₃F₂?BCF?is predicted,and the basic properties of the single layer are studied by means of the first principle calculation.The results show that the hydrogen saturated graphene like monolayer BCF is a super-soft nonlinear optical material which applicable in the short wavelength range.