The behaviour of Wannier excitons in very thin crystals

Abstract

A method of calculating the dependence on crystal thickness of the energies of different excitonic states is presented. The theory is developed for an isotropic semiconductor where the exciton may be treated in the effective mass approximation. The effect of the crystal surfaces are taken account of by means of image charges. Modifications to the isotropic theory are made allowing comparison of theory with experimental results on MoS₂.