Photoelectric Property Regulation Of Two-dimensional Copper Oxide

Among all the transition main group metal oxides,the nanostructure of copper oxide is used widely in the field of optical devices due to its unique photoelectric properties.The two-dimensional single-layer copper oxide has been used widely due to its good mechanical stability,stiffness,and excellent electronic characteristics.However,its indirect band gap characteristic is not conducive to the application in the field of optoelectronic devices.Changing the indirect band gap to a direct band gap has a great significance for the application of two-dimensional copper oxide in the optical field.Strain and doping are the most commonly methods to adjust the properties of two-dimensional materials.This paper systematically explores the electronic and optical properties of two-dimensional copper oxide under strain and doping.We have achieved the purpose of regulating the photoelectric performance of two-dimensional single-layer copper oxide.The specific research contents and results are as follows:1.We construct the two-dimensional copper oxide supercell model,the strained two-dimensional copper oxide supercell model,and the doped two-dimensional copper oxide supercell model.The magnetic,electrical,and optical properties of two-dimensional copper oxide are calculated by first-principles.It is concluded that the magnetic properties of the two-dimensional copper oxide are antiferromagnetic and it is mainly contributed by copper atom.The band structure is indirect band gap,and the bottom of the conduction band is mainly composed of d-layer orbitals of copper atom,the top of the valence band is mainly composed of p-layer orbitals of oxygen atom.2.We calculate the magnetic,electrical,and optical properties of two-dimensional copper oxide under-10%to 10%uniaxial strain and-10%to 18%biaxial strain.The calculation results show that both uniaxial and biaxial strains can change the band gap of two-dimensional copper oxide.,the light absorption appears red shift or blue shift in the low energy region.The magnetism is changed from antiferromagnetic to ferromagnetic and the band structure is changed from indirect bandgap to direct bandgap by uniaxial tensile strain,the effective mass of electrons decreases and the electron mobility increases.The top of the valence band moves from K to M by the biaxial tensile strain of 10%,the effective mass of holes increases significantly,and the hole carrier mobility decreases.3.We calculate the magnetic,electrical,and optical properties of two-dimensional copper oxide by doping the four elements Ag,Zn,Ni,and Co at three concentrations of 6.25%,12.5%,and 25%respectively.The calculation results show that the doping of the four elements is easier to achieve in a copper-rich environment,and the doping structure is more stable.The d-layer electron of four elements are doped in the forbidden band can effectively change the band structure.The narrower forbidden band can increase the probability of electrons jumping from the top of the valence band to the bottom of the conduction band.The light absorption intensity of copper oxide increases significantly.Especially,when concentration of doping Ni is 25%,the two-dimensional copper oxide is semi-metallic ferromagnetic,it has a high light absorption intensity,and the spin polarization near the Fermi surface is 100%,the electron transition from the valence band to the conduction band does not need any energy.