Ultraviolet photoelectron spectroscopy and scanning tunnelling microscopy of silver and copper clusters on HOPG, noble metals and rare gas layers

摘要

In terms of present and future applications of noble metal nanoparticles it is important to understand the interaction between metal clusters and their surrounding environment, especially with surfaces. Therefore the investigation of the geometric structure and electronic properties of clusters deposited on surfaces is of great importance. In this thesis silver and copper clusters were deposited on HOPG, noble metals and rare gas layers and investigated with ultraviolet photoelectron spectroscopy (UPS) and scanning tunnelling microscopy (STM). The geometric structure dependent on the cluster surface interaction was investigated with STM. In the case of silver clusters deposited on a gold substrate a strong cluster surface interaction leads to a layered structure of the deposited clusters. The electronic structure of silver and copper clusters was investigated with UPS for clusters deposited on different surfaces. A cluster size dependent electronic structure could be detected for all substrates. UPS measurements of deposited clusters on rare gas layers showed electronic quantisation within the s-p electronic structure, which was compared with results of UPS measurements of free beam clusters. Similarities could be observed, especially for copper clusters with 147 atoms.