The Growth Of Doped PWO Crystals And The Theoretical Calculation Of Density Function

In this paper, two different Pb doped PbWO4 crystals with various Pb/W ratios (1.01, 1.02), three PbWO4 crystals with different PbF2 doped concentrations (150×10-6, 250×10-6, 400×10-6), and as with Nb(500×10-6): Mo(1000×10-6): PWO for comparison, La(500×10-6): PWO, La(500×10-6): Mo(1000×10-6): PWO crystals were grown by Czochralski method. The influence of impurities on the crystal optical property were investigated.Ultraviolet spectrum revealed: Pb doped PWO, F doped PWO and pure PWO crystals have the same absorption edge, but the La doped, Nb5+-Mo6+ co-doped, La3+-Mo6+ co-doped make it shift to the longer wavelength; the impurity ions influence the transmittance of PWO in 420nm, PWO crystal with [Pb]/[W]=1.02 is better than [Pb]/[W]=1.01 and pure crystal, the La3+ doped, Nb5+-Mo6+ co-doped PWO and with the higher F doped level decreased the 420nm absorption, but the La3+-Mo6+ co-doped crystal doesn't improve it.All kinds of PWO crystals showed the body-centered tetragonal structure in the Raman spectra. The peak related to Pb vibration was broadened due to Pb, La, Nb occupying the VPb position; For Mo and F doping, respectively, occupy the W and O position make the outer model of WO42- groups broadened.There were no new peaks in the doped-crystal X ray diffraction patterns, but the intensity and the position of peak are different from pure one, so the doped ions altered the lattice parameters: Pb2+ occupy the VPb position maked the lattice volume increase, but the PbF2 and Nb-Mo co-doped are opposite due to Nb5+, F-, Mo6+ occupying the Pb2+, O2-, W6+ position respectively.At the same time, the plane-wave pseudopotential method of Density Functional Theory is used to study the energy band structure, the densities of states and optical properties of pure PWO and doped PWO crystals.Compared with the analysis result, research their connectivity. Calculation results showed that those impurities influnced the energy band structure, the densities of states and optical properties of pure PWO crystal. Through the Final energy, the positions of La3+ and VPb in La: PWO crysal are known. Compared the UV...