Excitons and energetic bands structure of ZnP2-С2h 5 crystals

Abstract

Reflectivity and transmittance spectra of ZnP2-C2h 5 crystals in the region of A, B and C excitons and E>Eg had been researched. The spectra had been calculated using dispersion correlations and the Kramers-Kronig correlations. The exciton parameters and optical functions n, k, ε1 and ε2 had been determined for all excitons. The changes of the damping factor γ, the transversal-longitudinal ΔLT exciton splitting Г2¯(z), and the exciton mass M in dependence on temperature had been revealed. The effective electron mass mc *=0,23m0 had been determined. It was shown that the holes mass mV1 *=4,27m0 for Е║с, k║а and E║b, k║a polarizations and mV1 *=0,55m0 for E║a, k║в polarizations. The energies of electronic transitions from V1, V2 and V3 zones into C1 zone and the symmetry of zones in the Г point had been determined. The splitting value of V1-V2 zones had been determined as being equal 92meV and V2 - V3 equals 143.6meV. The singularity of optical functions n, k, ε1, ε2, d2ε1/dE2 and d2ε2/dE2 had been determined inside the energy interval 1 – 10eV and were interpreted basing on the theoretical zone calculations.