CATION SURFACE EXCITONS IN SB/III-V INTERFACES

A complete study of the evolution of the surface cation excitons in III-V semiconductor compounds as a function of the Sb coverage is presented. Electron-energy-loss and yield spectroscopies (constant initial state, constant final state) on the Sb/GaAs(110) and Sb/InP(110) interfaces have been performed. The excitons for Sb/InP(110) and Sb/GaAs(110) systems are still present up to coverages of at least one monolayer, confirming an unreactive growth mechanism. The different growth morphology, depositing Sb on GaAs(110) and InP(110) in the submonolayer coverage, is discussed. The surface-exciton behavior is monotonically decreasing for Ga, in agreement with the scanning-tunneling-microscopy growth-morphology picture. For the Sb/InP system, the In and P sites are not equivalent in different stages of the monolayer formation.