Investigation of diamond nanostructures with incorporated color centers

Diamond is a material with excellent properties due to its structure and composition. Its crystal lattice is a perfect host of different defect centers, so-called color centers, whose properties, especially the capability of emitting single photons, can serve in quantum information technologies (QIT). As a high refractive index material only a small part of the photons emitted by these color centers in diamond can be collected. To enhance the photon collection efficiency photonic structures are necessary. They can be fabricated by nanostructuring techniques, which however are not trivial for diamond due to its chemical inertness. This thesis deals with the fabrication progress of diamond photonic structures, such as pillars and photonic crystal slabs, and the incorporation of NV and SiV centers into these structures. In this context different mask materials and etching parameters in the structuring process as well as different incorporation methods were part of the investigations. Challenges regarding the technological strategy and the creation of color centers were addressed. The thesis starts with an introductory chapter that highlights diamond as material, especially its optical properties. It also covers the introduction of color centers in diamond and leads to the photonic structures that were used in this work. Chapter 2 gives an overview over diamond growth, including hot filament chemical vapor deposition of diamond on different substrates, site-controlled deposition and the homoepitaxial overgrowth of existing structures. The fabrication of diamond photonic structures namely pillars and photonic crystal slabs, and the analysis of the morphological results are presented in Chapter 3. In addition, this chapter also covers the development of a planarization process for the rough nanocrystalline diamond surface. Finally, Chapter 4 contains the optical characterization (fluorescence mapping and photoluminescence) of selected single diamond nanocrystals and selected fabricated diamond photonic structures. The thesis closes with a summary and explains possibilities for the future work.