Electronic surface properties of III–V semiconductors: Excitonic effects, band-bending effects, and interactions with Au and O adsorbate layers

Photoemission studies of valence bands, core levels, empty surface states, and band bending for cleaved GaAs (110) are described. These studies show that there are no intrinsic band-gap surface states for GaAs (110), and that large (approx. greater than 0.5 eV) excitronic binding energies are involved in core-level-to-empty-surface-state transitions (e.g., using yield spectroscopy or electron energy-loss spectroscopy). Studies of the effects on chemisorbed oxygen and thin Au overlayers on InAs (110) and GaAs (110) surfaces are also described. Trends and correlations in III–V semiconductor empty surface states are discussed.