Electronic Structure And Physical Properties Of Doping And Vacancy Ga₂O₃

β-Ga₂O₃ has been widely used in deep UV detectors,photolithography,photovoltaic solar systems,electric vehicles and other high-power devices due to its ultra wide band gap（4.90 e V at room temperature）,unique ultraviolet transmission characteristics,high breakdown electric field strength,and low-cost quantitative production.However,the poor conductivity of β-Ga₂O₃ hinders its application as a transparent conductive oxide（TCO）.Doping and vacancies are effective ways to improve the photoelectric properties of materials,but there are few literatures on the impact of doping atomic number,doping and vacancies coexisting on β-Ga₂O₃.In this paper,the electronic structure and physical properties of transition metal doped β-Ga₂O₃ are systematically studied.Then Si-doped β-Ga₂O₃ is discussed.Finally,the influence of Si doping with vacancy on the structural,electronic,optical properties of β-Ga₂O₃ are analyzed based on the first-principles calculations.The results show that:1.All systems in this paper make the volume of β-Ga₂O₃ slightly change,but there is no lattice distortion.All systems are easy to form and are more stable than intrinsic β-Ga₂O₃.All the systems are direct bandgap semiconductors without damaging the semiconductor properties of the materials.2.When transition metal doped β-Ga₂O₃,the Ti-doped β-Ga₂O₃ is easily formed,followed by V,Cr,Sc,Fe,Mn,Co,Ni,Cu,and Zn doping.Some bands change regularly with the increase of atomic number.All systems become degraded semiconductors after doping which improves the conductivity of β-Ga₂O₃.All doping will make the β-Ga₂O₃ red shift.Among them,the absorption intensity of Cu doping in the visible light range is significantly improved.3.The physical properties of Si doped β-Ga₂O₃ at different positions were studied.The results show that the Si-Ga2 is the easiest to form,followed by Si-Ga1,Si-O1,Si-O3,Si-O2.When Si is doped with Ga,the band gap is slightly reduced,and the conduction band valence band changes little.When Si replaces O,impurity levels are generated in the band gap,and the conduction band and valence band move to lower energy levels by a large margin,which will help light absorption and β-Ga₂O₃ conductivity.When Si is doped with Ga,the absorption edge of the system has a slight blue shift.However,the system has a red shift,and the absorption in the visible light range is enhanced when Si is doped at the O site.Among them,Si-O3 has the strongest absorption in the visible light range.Each doping system is a degenerate semiconductor.4.The study of the influence of Ga and O vacancies on the electrical and optical properties of gallium oxide found that O vacancies are easier to form than Ga vacancies.Each vacancy will produce an impurity level,which makes the system red shift.Among them,O vacancy absorb is stronger in the visible light range.In addition,Ga₂O₃-VO（gallium oxide with oxygen vacancies）has electron carriers,which has n-type conductivity.5.Study the influence of the coexistence of vacancy and doping on the electrical and optical properties of gallium oxide,and find that the coexistence of doping and vacancy is more stable than the vacancy system.The conductivity of β-Ga₂O₃ increases,the absorption edge is red-shifted,and the absorption is strong in the visible range.Among them,Si Ga₂O₃VO（Si doped β-Ga₂O₃ containing O vacancies）is better than Si Ga₂O₃VGa（Si dopedβ-Ga₂O₃ containing Ga vacancies）in light absorption,but the conductivity is opposite.