Electronic Structures And Optical Properties Of Metal(Cu,Ag,Au):MgF2Crystal

MgF2crystal is widely used in the design and development of various optical thin films and Metal ceramic film, because of it excellent properties: Low refractive index, wide band gap, low absorption in Visible and near-infrared wavelengths, good Thermal stability and so on. The interaction can inevitably produce between Film and substrate, this may affect the microstructure and the related performance, So it has important significance in doping in film studies. Due to the limitation of the experimental research, atomic level of numerical simulations are particularly important. My article based on the density functional theory to research on the influence of the metal(Cu, Ag, Au):MgF2system. The main research contents are as follows:(1) Based on the density functional pseudopotential method, the geometries, electronic structures and optical properties of MgF2with different mass fraction of Cu doping (2.08atomic%,4.16atomic%and6.24atomic%) are compared in detail. Cu substitution of the Mg sites induces an effective reduction of the band gap of MgF2; and the band gap is continuously reduced with increasing Cu doping level. Also, the calculations show that the refractive index and absorption increase with increasing Cu doping. More importantly, an absorption around4eV is found. The mechanisms of this transition in the doped and undoped material are discussed. The Cu doped MgF2system could be a potential candidate for photoelectrochemical applications.(2) Based on the density functional pseudopotential method, the geometries, electronic structures and optical properties of MgF2with different mass fraction of Ag and Au doping (2.08atomic%and4.16atomic%) are compared in detail. Ag and Au substitution of the Mg sites induces an effective reduction of the band gap of MgF2; and the band gap is continuously reduced with increasing Ag and Au doping level. Also, the calculations show that the refractive index and absorption increase with increasing Ag and Au doping. But in4eV place, we found no absorption peaks like Cu.