Chemical trend of reflectance difference spectra of anion-rich compound semiconductor surfaces

Reflectance difference spectra of anion-covered GaAs 001.and 110.surfaces are calculated. By varying atom kinds of top-layer anions from N to P, As, and Sb, the spectral peak shifts toward lower energy, sharpens, and becomes large, being in good agreement with experiments. It is shown that these changes are closely related to the localization nature of anion dangling bond states at the surface and reflect the atomic orbital energies of anion atoms. q2000 Elsevier Science B.V. All rights reserved.