Investigations of the role of physisorbed hydrogen in STM experiments
FacultiesFakultät für Naturwissenschaften
The present dissertation contains three major objectives. The first is an improvement of the evaluation process of IETS data using Wavelet analysis. This requires a detailed understanding of all parameters especially the temperatures of tip and sample. Therefore, the second one is the calibration of these temperatures using a superconductive sample. Further influences of the tip on topography and spectroscopy are studied in the third objective, where the influence of hydrogen in the tunneling junction is investigated. It will be shown that the material of the tip plays a significant role. Where the hydrogen dissociates at a tungsten tip leading to a modified imaging mechanism, it is trapped in the junction when using silver tips. The latter is also responsible for characteristic features in spectroscopy. It will be shown that these features can be deduced from specific vibrational modes of a single molecule in the junction. Due to a separation dependent potential, forces are generated causing a deflection of the tip apex. It will be seen that the apex of silver tips are surprisingly soft.
Subject HeadingsInelastische Elektronen-Tunnelspektroskopie [GND]
Tunneling spectroscopy [LCSH]