Electronic band structure of cubic CdSe determined by angle-resolved photoemission: Cd 4⁢𝑑 and valence-level states

The valence-band structure of epitaxially grown cubic CdSe along the 𝛤−𝐾−𝑋 direction is determined experimentally using angle-resolved photoelectron spectroscopy on the basis of the free-electron final band model. In the upper valence band the three main branches are determined from normal emission spectra over the range from 15 to 90 eV photon energy, and are found to conform with the general shape expected from this class of materials. The Cd 4⁢𝑑 level exhibits considerable dispersion, which is reflected in the spectra. The experimental bands are compared with several calculations based on different schemes, and best agreement with respect to dispersion and binding energies is found for a calculation that takes into account electron self-interaction and relaxation.