Density Functional Theory Study On Photoelectric Properties Of Aluminum-Doped Gallium Arsenide Material

Semiconductor material technology is the core of the electronics and microelectronics technology industry.Since the 20th century,with the rapid development of electronics and microelectronics technology,semiconductor material technology has also advanced rapidly.Among them,GaAs is a semiconductor material that has attracted much attention,and its photoelectric characteristics are superior and its application is also very extensive.At the same time as the rapid development of semiconductor manufacturing processes,researchers have found a way to change the material properties,using different doping methods to do different impurities in the raw materials to obtain unique semiconductor materials.In this paper,the first principle calculation method based on density functional theory?DFT?is used to study the characteristics of Al atoms instead of Ga atoms doped GaAs materials(Al_xGa_1-x-x As).The following research results are obtained:?1?The effects of Al doping on the electronic structure and energy band of GaAs materials with Al composition of 3.13%,6.25%and 12.5%were calculated.The results show that after doping Al,the impurity level is introduced to make Al doped arsenic.The forbidden band width of the gallium material is reduced,and the forbidden band widths of the Al composition of3.13%,6.25%,and 12.5%are 0.63eV,0.68eV,and 0.73eV,respectively,and are smaller than the forbidden band width of the intrinsic GaAs.But the material is still a direct bandgap semiconductor.As the influence of the Al composition increases,the degree of hybridization of the energy level increases,and the peak value of the total density decreases linearly.?2?The effects of Al doping on the optical properties of GaAs materials with Al composition of 3.13%,6.25%and 12.5%were analyzed.The results show that the static dielectric constant of the system is slightly larger than the static dielectric of intrinsic GaAs after Al doping.The constant,and as the Al composition increases,the peaks of the static dielectric constant,refractive index,and energy loss function decrease,the absorption coefficient increases,and the static reflectance fluctuates less.?3?The effects of different doping positions of Al components on the doped GaAs characteristics are discussed.The results show that the Al composition is 3.13%and the doping position is the center,the static dielectric constant is the largest,the absorption coefficient,the reflectivity,the reflectance and the extinction are blue-shifted.When doping at the surface position,the energy loss spectrum has a significant blue shift phenomenon.The Al composition is 6.25%.When the Al atoms are spaced apart,the absorption,the energy loss,and the reflectivity are blue-shifted,and the peak of the energy loss is the largest.The Al composition is12.5%.When the[0 1 0]crystal orientation is doped,the forbidden band width is the largest,and the conduction band bottom has no impurity level.The forbidden band width is twice the doping at other positions.The complex dielectric constant and absorption,the coefficient,reflectivity and extinction are blue-shifted,and the energy loss is obviously red-shifted in the high-energy stage.