DETERMINATION OF CONDUCTION-BAND STATES IN GAAS(110), INP(110), AND INAS(110)

Angle-resolved constant-initial-state spectroscopy (ARCIS) from the valence-band maximum as initial state was used to determine conduction-band energies at the GAMMA point for GaAs, InP, and InAs. With the help of nonlocal empirical-pseudopotential (EPM) calculations structure in the ARCIS spectra up to 20 eV could be assigned to particular interband transitions. A group of transitions around 26 eV is derived from the pseudopotential split (220)-umklapp process at the Brillouin-zone center. Above 30 eV there appears to be no correspondence between conduction-band states as calculated in the EPM framework and structure in the spectra. Autoionizing resonances due to surface core excitons have been observed. From their energies surface-core-exciton binding energies in the range 0.5-1.5 eV have been determined for the three compounds.