Attivazione di difetti luminescenti in carburo di silicio 4H mediante l'utilizzo di laser impulsati

Silicon carbide (SiC) is a promising solid-state platform for photonics in quantum technologies, due to its outstanding physical properties and its maturity for opto-electronic device integration. Recent advances in mass manufacturing SiC fabrication techniques led to the commercial availability of high-quality substrates for the fabrication of solid-state single-photon sources upon the controlled fabrication of individual luminescent lattice defects, commonly known as color centers. The goal of this thesis is the assessment of a novel post-irradiation annealing technique relying on pulsed laser processing for the optical activation of color centers, and subsequent PL characterization of defects in SiC following ion irradiation and implantation. This processing technique, not explored so far in the scientific literature for the formation of optically-active defects, relies on the exploitation of a ns-pulsed laser focused at the micrometer scale to locally increase the temperature of the material, thus allowing the diffusion of radiation-induced vacancies and the formation of stable defective complexes upon spatially-selective rapid thermal annealing. This process can be performed iteratively at a high repetition rate, thus reducing the overall processing time with respect to standard furnace-based processes and offering a substantial increase (potentially, deterministic) in the efficiency of the defects activation. The analyzed samples were obtained from a single-crystal 4H-SiC wafer and subsequently irradiated with He2+ ions at 1.5 MeV. The activation process was performed via pulsed-laser annealing, using a Nd:YAG ns-pulsed spanning the parameter space of its emission wavelength, optical power density and pulses number to identify the most effective configuration for luminescent defects formation. The characterization was performed through single-photon-sensitive confocal microscopy mapping and spectroscopic analysis (UV-VIS and micro-Raman spectroscopy). Finally, optically-detected magnetic resonance (ODMR) measurements were performed to assess the optical addressability of the spin properties of the fabricated color centers. These results demonstrate the effectiveness of the proposed approach, which may lead, upon refinement of the pulsed-laser annealing procedure, to deterministic activation of luminescent defects following ion irradiation and implantation.