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Luminescence properties of SiV-centers in diamond diodes

: Tegetmeyer, Björn
: Ambacher, Oliver

Freiburg/Brsg., 2018, II, 105 S.
Freiburg/Brsg., Univ., Diss., 2018
Fraunhofer IAF ()

The silicon-vacancy center (SiV-center) is a promising candidate for quantum-physical applications due to its physical properties. Besides its narrowband photon emission at 738 nm wavelength, it shows a high photo-stability already at ambient conditions. Contrary to the well-known and extensively studied nitrogen-vacancy center (NV-center), the physical properties of the silicon-vacancy center are not known well enough at the moment for actual applications in the area of quantum-computing or quantum communication. Especially the possibility of electrical excitation and the luminescence properties of different charge-states of the SiV-center are not sufficiently proven. The present work intends to narrow this gap. Therefore, after initial optimization of the diamond growth-processes in ellipsoidal cavity Microwave Plasma Enhanced Chemical Vapor Deposition (MWPECVD) reactors developed at Fraunhofer IAF, diamond PIN and Schottky-diodes with in-situ incorporated as well as implanted silicon-vacancy centers, respectively, were fabricated. With these devices, the electrical excitability of the luminescence of silicon-vacancy centers was studied. Additionally, experiments for exploring the luminescence properties of the silicon-vacancy center at different surface terminations (hydrogen-, oxygen-, and fluorine-termination) influencing its charge-state were performed. For a more detailed investigation of the SiV charge states, a two dimensional Schottky-diode was fabricated from diamond, allowing to control the charge states actively and examine the resulting optical properties of the silicon-vacancy center. An ATLAS-simulation of the luminescence behavior observed in the two-dimensional Schottky-diode was performed to explain the physical processes and the experimental observation. The simulation indicates, that a charge state shift between SiV0 and SiV−(possibly even to SiV2−, which have been predicted theoretically), could be observed in the present experiment. Thereby, it could be shown, that a shift of the charge state of the SiV-centers from neutral to negative charge state could qualitatively explain the luminescence behavior observed. The methods as well as the obtained results, embedded in the physical backgrounds are extensively discussed and interpreted in the present thesis.