Exciton spectra of CuInSe2 crystals

Abstract

The excitonic reflectivity spectra and the wave-length derivative reflection spectra have been investigated for CuInSe2 crystals. The n =1, n =2 and n = 3 states of A, B and C exciton series are revealed and the contours of exciton lines (n=1) are calculated. The exciton binding energies and exact values of the band gaps of all three intervals Γ7 (V1) – Γ6 (C1), Γ6 (V2) – Γ6 (C1), Γ7 (V3) – Γ6 (C1) have been also calculated. Data of the splitting due to crystal-field and spin-orbit interaction are determined. The parameters of excitons and energy bands for the region of interband interval minimum have been determined as well. The band model in the Γ, N and T points of the Brillouin zone is proposed.