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This thesis is about the development of a tool to implement vertical resolution within a scanning electron microscope (SEM). This becomes necessary as due to the principle of an SEM it is only possible to get vertical resolution by proper focussing, which is limited to some micrometers. As it is important to get access to height information of a sample during several processes in the SEM, especially when performing nanomanipulation, an additional tool is inserted into the SEM to provide the missing information. This so called Nanofinger® was originally invented by Klocke Nanotechnik GmbH in Aachen. It is mounted on a three-axis manipulator and operates similar to an atomic force microscope (AFM) to perform linescans on a given structure or to simply retrieve surface coordinates at certain positions on the sample.As the former Nanofinger® did not fulfill the requirements, a new concept to improve the Nanofinger® was established. The new Nanofinger® was realized to operate in the SEM. To succeed in this project, first, the issues of the old Nanofinger® have been investigated to develop a concept for the improvements. In the following part of this thesis, the development and construction of the new Nanofinger® is described. This includes the new scanhead as well as the fabrication of the sensors. The most important aspect of the optimization is the achieved vertical resolution. The noise in der vertical direction is 1 nm, limited by the manipulator. Moreover, structures of 2 nm could be resolved. A slim geometry with a height of 3 mm allows the operation of the Nanofinger® at low working distances under the SEM. Also, the Nanofinger® can be operated easier than before, allowing users with little knowledge about the AFM to use the Nanofinger®. This includes a distinct resonance spectrum of the sensors and a simple tip exchange. Besides of the hardware, also the software was improved to add additional functionality to the Nanofinger®. This is a feedback loop which is directly designed for this special tool. Moreover, the electrostatic force microscopy (EFM) mode was implemented. To demonstrate the improved performance of the new Nanofinger® beyond the quality of the aquired linescans, local anodic oxidation (LAO) of graphene achieved with the Nanofinger® is shown in chapter 5. After a brief overview of LAO of graphene, the sample preparation of monolayer graphene on hexagonal boron nitride (hBN) is described. Attention was paid on investigating graphene within the SEM without contaminating the sample. The oxidation of graphene was successfully performed under vacuum conditions, achieving a linewidth down to 50 nm. The LAO was done within the SEM, supplying additional water up to a pressure of $3\times 10^{-5}$ mbar and a tip sample voltage of 10 V. Insulation of the cuts has been shown by directly contacting the graphene with the Nanofinger® and by doing EFM measurements within the SEM.

This work focuses on controlling the growth of EBID structures using Nanofinger technology, and the application of EBID technology to manipulate the electrical properties of graphene. By using new Nanofinger hardware, through the optimization of the measurement parameters, as well as a revised geometric arrangement of the Nanofinger in SEM, it was possible to achieve a range between 20 nm and 40 nm for the measurement resolution of the Nanofinger. This is remarkable, since the Nanofingers was, until then, mainly used to measure structures in the micron range. Improving the accuracy by two orders of magnitude has been achieved. In this optimized configuration, it is now possible to control the growth of EBID structures in situ. The EBID process is to proceed in the usual way, through a nano-finger measurement only when needed that the profile of the grown structure is measured. This process is performed iteratively until the the desired height has been reached. This is a significant step forward in controling the lateral dimensions of EBID structure instead of only using an AFM measurement. This meant in most cases, that the sample has to be transported to a spatially separated AFM. This would lead to impurities, which can complicate further growth. Thus, it is now possible to achieve faster and more efficient optimization of the growth parameters of EBID structures, which in turn leads to a better understanding of the structures themselves. The so controlled EBID technology can now be used in order to manipulate the properties of semiconductor materials, in particular graphene. This graphene is generally produced by mechanical exfoliation and contacted by the application of electrodes. The so-prepared flakes can now be examined in terms of their electrical properties. In the space between the electrodes, the application or the removal of adsorbates is possible resulting in a change in mobility in the flake. It has been shown that the application of EBID deposits leads to a drastic reduction of the mobility. There was found no correlation between the magnitude of the effect and the nature of the precursor gas used for the EBID process. This may be due to, among other things the highly variable preparation parameters, because the samples differ by the type and size of the flakes and the contact. It was also shown that current annealing or storage under vacuum can reverse this effect, in part, because this results in an increase of mobility. These effects are highly reproducable, so that a long series of measurements can be carried out, in which the mobility can be increased and decreased alternately. This is an important point, since it provides an opportunity to determine the electrical properties of graphene in a certain context and adapt the applications. The methods explored in this work represent a basis for further progress on the profile of nm-structures, and the other in the manipulation of the properties of semiconductors in the future. Thus, a wider field of application of the Nanofinger it is also possible to control lithography structures in resists, leading to an improved transfer of the structures. Furthermore, a variety of other applications are conceivable which can be Nanofinger and Nanomanipulator based. Thus, the mechanical properties can also be investigated by means force sensors which are mounted on the manipulator instead of the Nanofinger. Again, the manipulation of the mechanical properties of adsorbates is possible. Also spin-based properties with regard to changes of EBID adsorbates can be studied in addition to the electrical properties. For this purpose, the same samples can be used as presented here. Important variables in the spin-based semiconductor technology can also be obtained in addition to the mobility in the future in addition. These includes, for example, spin dephasing, spin diffusion lengths, and the magnitude of the spin signal.

Nanofingers of gold covered by porphyrins are prepared by a combination I of atomic manipulation and surface self-organization. A submonolayer of zinc(II) 5,10,15,20-tetrakis(4-tert-butylphenyl)-porphyrin (ZnTBPP) axially ligated to a self-assembled monolayer of 4-aminothiophenol (4-ATP) on Au(111) is prepared and studied using a combination of ultrahigh vacuum techniques. Under the electric field produced by the STM tip, the relatively weakly bound Au surface atoms along the discommensuration lines become mobile due to the strong bond to 4-ATP, while the tendency of the porphyrins towards self-assembly result in a collective motion of gold clusters. The clusters diffuse onto the surface following well-defined pathways along the [11 (2) over bar] direction and then reach the step edges where they assembled, thus forming nanofingers. First-principles density functional theory calculations demonstrate the reduction of the binding energies between the surface gold clusters and the substrate induced by adsorption of thiols. Scanning tunneling microscopy images show assemblies across three adjacent discommensuration lines of the Au (111)-(22 x root 3) reconstruction, which collectively diffuse along these lines to form islands nucleated at step edges.