Spectral Analysis of Photoemissive Yields in GaAs and Related Crystals

The strongest optical reflectivity peak at 5 eV in GaAs and the corresponding dip at 5 eV in the photoemissive-yield curve have long been associated with X₅ᵥ→X1c transitions. Since recent experimental and theoretical studies indicate that X1c-X₅ᵥ=4.2±0.1 eV, this association is invalid. Accordingly, most of the earlier estimates of X1c-X₅ᵥ and X3c-X₅ᵥ in GaAs and related crystals will have to be revised, as will empirical band models based on these estimates. An improved energy-band model for GaAs is reported.