Core-level photoemission study of the InAs/CdSe nanocrystalline system -: art. no. 045301

We have applied the technique of core-level photoemission spectroscopy with synchrotron radiation to a study of the interface in the colloidally prepared InAs/CdSe core/shell nanocrystal system. We find that As-Se and In-Se chemical bonds dominate the interface which we may describe as "Se rich." The surface states observed for In and As of the pure InAs nanocrystals are successfully removed by growth of the CdSe shell layer. We discuss how the removal of these "surface charge traps" causes a large increase in the photoluminescence yield compared with that of the pure InAs nanocrystal.