AbstractMgO crystals have been exposed to vacuum ultraviolet (VUV) radiation from a synchrotron, with energies up to 9 eV. It is concluded that bulk excitons, play an important role in the diffusion of energy inside MgO crystals, resulting in 5.77 eV (215 nm) surface exciton emission. We discuss the possible use in ZnO‐MgO core‐shell quantum‐dots (QDs), including energy band offset and charge carrier transfer.