The excitonic absorption of CdS under pressure

Abstract
We have investigated the pressure dependence of the absorption edge of tlie EA-EB- and the EC-excitons of 1pi thick CtlS(hex) crystal slabs. We obtaiurd dEΘ/dP =dEc/dP = 47±3 meV/GPa for T=300K and dEA/dP= dEB/dP = 43±3 meV/GPa for T=78K. With tliese values we were able to determine the crystal-field splitting (68f4 nieV) aid the spin-orbit splitting (26±2 meV). The resulting pressure shifts of tlie rxcitonic energies were in agreement witli a κ · p-calculation of tlie transition energies using tlie perturbation niatrix of G.E. Pikus for Δso ≫ Δc. The refractive Index n‖c was iiieasured for T=300K up to 2.2 GPa and described by Marples Model.