Exciton spectra and energy band structure of CuAlSe2 crystals

Abstract

The main exciton parameters and the refined values of the energy intervals V1(Г7) - C1(Г6), V2(Г6) - C1(Г6) and V3(Г7) - C1(Г6) in CuAlSe2 crystals are discussed. The crystal field and spin-orbit splitting of the balance band are determined. The effective masses of electrons (m*C1), and holes (m* V1, m*V2, m*V3) are estimated. The contours of reflectivity spectra at high photon energies (Е Еg) are calculated on the basis of Kramers-Kronig relations. The spectral dependences of the real and imaginary parts of the dielectric function, of the refractive indexes no, ne, and the absorption coefficient were determined. The experimental data are discussed on the basis of theoretical band structure calculations.