| Popis: |
Synthetic diamond is a versatile material with applications in many elds of everyday life. As a gemstone, it decorates ngers, necks, wrists and is perfectly brilliant-cut. Being the hardest material on earth makes it ideal for use in the drilling and cutting industry. While the high thermal conductivity of diamond makes it an attractive candidate for applications in power electronics industry as effective heat sinks, another use of ultra pure diamond lies in future quantum technology. Atomic sized defects (or colour centres) within the diamond have unique quantum mechanical properties and make them promising candidates to perform exciting quantum sensing, quantum computing and quantum communication experiments. In the future this technology platform might lead to applications and eventually products which will change the way we compute, communicate and live. The nitrogen vacancy (NV) centre is one of the most extensively studied defects in diamond and due to its unique properties can be used as a nano scale nuclear magnetic resonance (NMR) sensor and enable the analysis of single molecules or proteins. Another colour centre, the so called silicon vacancy (SiV) can be used for quantum communication due to its unique optical properties. Large distance entanglement of solid state spins or quantum repeater nodes are future components of quantum networks based on this spin-photon interface. In order to make diamond material usable in potential future applications a high degree of reliability, reproducibility and control during the fabrication process is necessary. Parameters such as density, depth from the diamond surface, the depth distribution as well as coherence properties and optical stability and homogeneity of the colour centres all need to be optimised for the speci c application. It is therefore essential to understand the NV or SiV creation process as well as to have a high degree of control on the processing parameters which have a major influence on the (spin) properties of the colour centres. In this thesis, optically stable centres could be engineered despite their proximity to charge traps and noise sources from the diamond surface. The effect of surface modi cation techniques is evaluated and found to be a powerful post-processing step towards stabilisation and controlled generation of shallow, stable SiV centres. The tailored depth-positioning of individual NV centres is a key requirement for future applications in nano NMR and hyperpolarisation. By adjusting the implantation angle with respect to the diamond surface and using optimised annealing recipes, insight into the creation process and influencing factors on the depth distribution and (spin) properties of shallow NV centres is gained. The experimental results are compared to simulations thus signi cantly improving the degree of control on the fabrication process. A better understanding of NV centre formation dynamics is fi nally achieved by utilising a unique feature of the ion implanter developed in this work. The capability of simultaneous annealing and implantation opens the door to a variety of experiments conducted with the goal of nding optimised NV formation conditions. Analysis of the creation effciency as well as benchmarking of the spin properties shine light onto promising routes for further research to establish a favoured fabrication process for NV centres as nanoscale sensors close to the diamond surface. |
