Study On The Bandgap Tunable Semiconductor Materials Of Gallium Indium Oxide

Ga₂O₃ as a new generation of wide band gap semiconductor materials,has a band gap of 4.9 e V.Ultrawideband gap makes Ga₂O₃ exhibit deep ULTRAVIOLET transmission characteristics as low as 250 nm,so it can be used to make short-wavelength optoelectronic devices.The band gap of In₂O₃ is generally less than 3.7e V,and the formation of indirect band gap with Ga₂O₃ ternary alloy semiconductor materials.By changing the content of Ga and In in the alloy material,the band gap of the material can be modulated between 3.7 and 4.9 e V.In addition,rare earth ions have good luminescence characteristics.In order to achieve efficient room temperature luminescence,it is necessary to select Ga₂O₃ and(Ga_1-xIn_x)₂O₃ as rare earth hosts,which has important research significance in the field of white light emitting diode（LED）.First of all,density functional theory（DFT）is used to calculate the energy band structure and state density of(Ga_1-xIn_x)₂O₃ alloy with different contents.The results show that the band gap ofβ-Ga₂O₃ alloy is 4.864 e V,andβ-(Ga_1-xIn_x)₂O₃ alloy has an indirect band gap structure.When the doping content changes,the band gap decreases from 4.517e V to 3.475 e V.In addition,the electronic density ofβ-(Ga_1-xIn_x)₂O₃ alloy is analyzed.The results show that the band gap is determined by the band In5s state and Ga4s state at the bottom of the conduction band and the O2p state at the top of the valence band.For c-(Ga_xIn_1-x)₂O₃ alloy,the band gap is 3.475 e V when the doping content is 0.25.The bottom of the conduction band is mainly composed of O2p,and the interband transition of the alloy mainly occurs between the valence band O2p state and the conduction band In5s,Ga4s state.In addition,gallium indium oxide band gap adjustable thin films were prepared by magnetron sputtering,and the effects of annealing temperature and atmosphere on the band gap were analyzed.The results of EDS show that the prepared films have high purity.XRD results show that(Ga_0.3In_0.7)₂O₃ films have higher crystallinity at 1000°C,while(Ga_0.7In_0.3)₂O₃ films have higher crystallinity at 900°C.The results of ultraviolet and visible transmission spectrum show that the transmittance of the film in the visible band is more than 80%.In addition,the band gap of the alloy increases with the increase of annealing temperature.The RMS roughness of the films is less than 5 nm under different annealing conditions,which indicates that the films have good surface quality.Finally,rare earth Eu₂O₃ and Ce O₂ doped Ga₂O₃ and(Ga_1-xIn_x)₂O₃ phosphors were synthesized by high temperature hydrothermal method,and the effects of different conditions on their luminescence properties were studied.Firstly,Eu₂O₃ was mixed into Ga₂O₃ powder,and thermal annealing was carried out at 700,750,800,850 and 900℃respectively.It was concluded that the phosphors annealed at 800℃showed the most obvious luminescence.Secondly,Ga₂O₃ powder was mixed with different contents of Eu₂O₃ powder.When Eu content was 0.03,the emission spectral intensity of phosphor sample was the largest.In addition,different contents of Ce O₂ sensitizer and Eu₂O₃ powder were mixed into Ga₂O₃.When the content of sensitizer was 0,the emission spectrum intensity of phosphors reached the maximum.Finally,(Ga_1-xIn_x)₂O₃ was mixed with Eu₂O₃.When the content of In was 0.3,(Ga_1-xIn_x)₂O₃ phosphor luminescence was the most obvious.