Theory of core excitons

The major chemical trends in the binding energies of intrinsic and extrinsic core excitons are predicted for zinc-blende semiconductors using an empirical tight-binding theory and localized empirical core-hole potentials. A transition from a shallow Wannier exciton to a deep Frenkel exciton is predicted for an exciton at a core-exciton absorption edge, depending on the chemical structure of the excited atom and the localization of the core hole. The theory is applied successfully to the bound and resonant Ga $3d$ core excitons in GaP, GaAs, and GaSb.