Electronic structure of titania surfaces modified by Au clusters

Full text: Metal clusters with a size of less than 100 atoms are suitable for modifying the electronic properties of semiconductor surfaces. In order to avoid agglomeration of the metal clusters and in order to retain their specific electronic structures, the coverage of the surface with metal clusters has to be kept below 10%. The main challenges in this field are to maintain the size and thus the properties of the metal clusters and to determine the electronic structure of the clusters. The first challenge is considered as one of the main challenges in the field of surface modification with metal clusters can be addressed by introducing defects on the metal oxide surface, specifically oxygen vacancies. The second challenge can be addressed by using experimental techniques which are exclusively sensitive for the electronic structure of the outermost layer. Metastable Induced Electron Spectroscopy (MIES) is such a technique and has been used successfully to determine the change in electronic structure due to the deposition of Au clusters. Applying techniques such as singular value decomposition, the changes of the electronic structure can even be quantified. (author)