Conventional and new growth phenomena during metal deposition on transition metal dichalcogenides
The present work goes far beyond the already known aspects of alkali metal adsorption on transition metal dichalcogenides and will consider it in a new and further manner. Until now, the investigations of this topic were restricted to only few metals like, e.g. alkali metals, which cannot be handled on a technological scale. In this thesis, technologically relevant adsorbate metals like chromium, silver or copper were chosen and the adsorbate structures were investigated by different experiments (SEM, EDX, AFM). One basic requirement for a systematic investigation is the conservation of constant preparation conditions. Therefore, a completely new preparation chamber had to be constructed. The successful operation of the chamber enables the variation of the deposition parameters (deposition amount, substrate temperature) systematically and offers the possibility to investigate the influence of the deposition parameters on the growth parameters and on the occuring structures. On the crystal surfaces a large unknown variety of structures can be observed, depending highly on the adsorbate/substrate system, amount of deposited metal and substrate temperature. This large variety was discussed in the context of existing theoretical models of growth phenomena and the dominating growth parameters. In addition to the interaction of adsorbate/substrate and the resulting destruction of the crystal surface, the diffusion length of the adsorbate atoms is identified as one dominating parameter for the structure formation. A new method for measuring this quantity demonstrates the distinct deviation from general growth concepts.