@article{AstakhovKrausSoltamovetal.2014, author = {Astakhov, Georgy V. and Kraus, Hannes and Soltamov, V. A. and Fuchs, Franziska and Simin, Dimitrij and Sperlich, Andreas and Baranov, P. G. and Dyakonov, Vladimir}, title = {Magnetic field and temperature sensing with atomic-scale spin defects in silicon carbide}, doi = {10.1038/srep05303}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-113025}, year = {2014}, abstract = {Quantum systems can provide outstanding performance in various sensing applications, ranging from bioscience to nanotechnology. Atomic-scale defects in silicon carbide are very attractive in this respect because of the technological advantages of this material and favorable optical and radio frequency spectral ranges to control these defects. We identified several, separately addressable spin-3/2 centers in the same silicon carbide crystal, which are immune to nonaxial strain fluctuations. Some of them are characterized by nearly temperature independent axial crystal fields, making these centers very attractive for vector magnetometry. Contrarily, the zero-field splitting of another center exhibits a giant thermal shift of -1.1 MHz/K at room temperature, which can be used for thermometry applications. We also discuss a synchronized composite clock exploiting spin centers with different thermal response.}, language = {en} } @phdthesis{Fuchs2015, author = {Fuchs, Franziska}, title = {Optical spectroscopy on silicon vacancy defects in silicon carbide}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-124071}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2015}, abstract = {This work sheds light on different aspects of the silicon vacancy in SiC: (1) Defect creation via irradiation is shown both with electrons and neutrons. Optical properties have been determined: the excitation of the vacancy is most efficient at excitation wavelengths between 720nm and 800nm. The PL decay yields a characteristic excited state lifetime of (6.3±0.6)ns. (2) Defect engineering, meaning the controlled creation of vacancies in SiC with varying neutron fluence. The defect density could be engineered over eight orders of magnitude. On the one hand, in the sample with highest emitter density, the huge PL signal could even be enhanced by factor of five via annealing mechanisms. On the other hand, in the low defect density samples, single defects with photostable room temperature NIR emission were doubtlessly proven. Their lifetime of around 7ns confirmed the value of the transient measurement. (3) Also electrical excitation of the defects has been demonstrated in a SiC LED structure. (4) The investigations revealed for the first time that silicon vacancies can even exist SiC nanocrystals down to sizes of about 60 nm. The defects in the nanocrystals show stable PL emission in the NIR and even magnetic resonance in the 600nm fraction. In conclusion, this work ascertains on the one hand basic properties of the silicon vacancy in silicon carbide. On the other hand, proof-of-principle measurements test the potential for various defect-based applications of the vacancy in SiC, and confirm the feasibility of e.g. electrically driven single photon sources or nanosensing applications in the near future.}, subject = {Siliciumcarbid}, language = {en} }