Electron trapping on Fe3+ sites in photodoped ZnO colloidal nanocrystals

The effects of photodoping on the electronic structure of Fe3+-doped ZnO colloidal nanocrystals are presented. We observe disappearance of the spectroscopic signatures attributed to both substitutional Fe3+ and interstitial Fe3+ in the ZnO host as a function of photodoping time, which precede the appearance of the well-known localized surface plasmon resonance from conduction band electrons in ZnO nanocrystals. These results suggest that the oxidation state of Fe3+ defects can be reversibly switched in ZnO nanocrystals.