Valence band alignment and work function of heteroepitaxial nanocrystals on GaAs(001)

Abstract

The differences in valence band structure and work function between heteroepitaxial nanocrystals and the surrounding substrate were measured with a spectroscopic photoemission and low energy electron microscope which allows laterally resolved photoemission spectroscopy. The nanocrystals were obtained by depositing nominally 2 and 4 monolayers (ML) of InAs on a Se-terminated GaAs(001) surface. The samples showed differences in the valence band edge energy and work function both between nanocrystals and substrate as well as between 2 and 4 ML. We suggest that Se termination of the nanocrystals is the reason for these differences.