Aufbau eines kombinierten Rasterkraft-/ Rastertunnelmikroskops und rasterkraftmikroskopische Untersuchungen an Thiophenverbindungen

Abstract

In this work the self-assembly properties of Thiophen-compounds on Mica and HOPG (Highly Ordered Pyrolythic Graphite) were studied. The samples were prepared in different techniques like drop-casting and spin-coating, the characterization of these thin films was done by Atomic Force Microscope (AFM) measurements in tapping mode. In detail two compounds of the Dihexyl-Ethylendioxythiophenes and one dendritic compound consisting of 90 Thiophenes were investigated. For those systems the long distance behaviour of the adsorbed molecules was investigated with AFM-measurements. Furthermore a combined Atomic-Force-/Scanning-Tunneling-Microscope (STM) was built up and was put into operation successfully. With this device one is able to obtain simultaneously not only the topography but also the local conductivity with one scan. The distance-control switches automatically between tunneling-current-control and force-control. This combined AFM/STM is an ideal tool for characterizing systems whose conductivity varies lateraly too much for stable STM-measurements in air.