First-principles Calculation Of Rare Earth Doped Black Phosphorus

As a new type of semiconductor material,the excellent electrical and optical properties of black phosphorus have attracted researchers both at home and abroad.In this paper,by the first principle calculation method,the band structure,density of States and optical properties of black phosphorus,N single doped black phosphorus,and rare earth elements(Sc,Y,La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb)are calculated.The results are shown as following.Firstly,the analysis of the band structure,density of States and optical properties of black phosphorus are calculated.The band gap is 0.967 e V,and the conduction band is mainly composed of 3p of P atom,while the valence band is mainly composed of 3p state and 3s state of P atom.From the graph of dielectric function real part of black phosphorus,it is known that the static dielectric constant is 6.55.There are two obvious peaks in the imaginary part of the dielectric function,respectively at 3.45 eV and5.69 eVTheabsorption.peak reached the maximum peak level of 2.44*105 cm-1 at 6.55 eV.The peak of the reflection spectrum is at 7.4eV,and the energy loss function peak is near 12.9eV.Secondly,the calculated band structure,density of States and optical properties of N doped black phosphorus,the band gap is slightly less than pure black phosphorus.After N doping,the N atoms interact with the surrounding P atoms,and the number of energy levels of the conduction band and valence band increases obviously.For the respect of the optical properties,static dielectric constant static dielectric constant of N doped with black phosphorus is less than it of black phosphorus,which represents the conductivitys enhanced.From the graphs of dielectric imaginary function of N doped black phosphorus and pure black phosphorus,absorption and reflection spectrum,it is found that the position of the main peak moves towards low energy,and the red shift occurs.Finally,through the calculation and analysis to the band structure,density of States and optical properties of rare earth doped and N co-doped with black phosphorus,it is seen from the band structure,Doping band gap less than the band gap of black phosphorus,in addition to the Ce and N co-doped and Yb doped,Ce and N co-doped black phosphorus conduction band and valence band shows coincidence metal band width,and the width of band gap of Yb doped black phosphorus to be slightly larger than the black phosphorus.The number of energy levels of the conduction band and valence band is also increased obviously,which is the interaction of rare earth elements with the surrounding P atoms after the single doping of rare earth elements and the co doping of N.From the density of states can be found from the Ce atom after doping,it is by 4f and Sc,with more states,Y,La single doped and co-doped state density peak is mainly composed of 3d,4d,5d state contribution,which is due to start from the Ce element with 4f electrons.See from the optical properties of the dielectric function,black phosphorus,rare earth elements and rare earth elements in black phosphorus single doped and N co-doped black phosphorus imaginary map,absorption spectra,reflectance spectra and energy loss,that the larger part of the difference in energy,when the energy is greater than 12.5eV,the change trend of convergence;comparison the imaginary part of the dielectric function,absorption peak position change peak,peak reflection spectrum and refraction spectrumpeak,peak positions are found to shift toward low energy,so we can judge the single doped and co-doped after red shift phenomenon.