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(a) Confocal image using 532 nm excitation and a 650 nm long-pass filter of the laser written dots area of the 6H-SiC. From the bottom brightest emission corresponds to dots fabricated with 230 nJ
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Optically active color centers in silicon carbide have attracted considerable attention in the past few years as candidates for quantum technologies such as single-photon sources, nanomagnetic resonance imaging, and spintronic devices. Control over defect position and their placement at the desired location within a chip, necessary to integrate the...
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Context 1
... results were seen in the 6H SiC, however, in this material fabrication was carried out only close to the surface. In Figure 4, we show the confocal image of the written area in the 6H SiC using 532 nm excitation compared to an SEM image of the same area. The spectral analysis shows the formation of emission at 900 nm however in this case the brightness was lower compared to the 4H material. ...
Citations
... Chen et al. created single V Si centers in 4H-SiC using laser writing without any post-annealing process and discussed the mechanism of the laser writing process [28]. Castelletto et al. prepared numerous V Si defect arrays in 4H-SiC and found that the number of color centers formed exhibited power-law scaling with the laser processing energy, indicating that the color centers were created by photoinduced ionization [29,30]. At present, the creation of 4H-SiC color centers technology is a relatively mature research topic, but the creation of V Si by the fs laser writing of 6H-SiC is rarely researched. ...
As a single photon source, silicon vacancy ( V Si ) centers in wide bandgap semiconductor silicon carbide (SiC) are expected to be used in quantum technology as spin qubits to participate in quantum sensing and quantum computing. Simultaneously, the new direct femtosecond (fs) laser writing technology has been successfully applied to preparing V Si s in SiC. In this study, 6H-SiC, which has been less studied, was used as the processed material. V Si center arrays were formed on the 6H-SiC surface using a 1030-nm-wavelength fs pulsed laser. The surface was characterized by white light microscopy, atomic force microscopy, and confocal photoluminescence (PL)/Raman spectrometry. The effect of fs laser energy, vector polarization, pulse number, and repetition rate on 6H-SiC V Si defect preparation was analyzed by measuring the V Si PL signal at 785-nm laser excitation. The results show that fs laser energy and pulse number greatly influence the preparation of the color center, which plays a key role in optimizing the yield of V Si s prepared by fs laser nanomachining.
With the rapid development of NV* color centers in silicon carbide, as a new candidate for quantum technologies, have attracted increasing attention in the past ten years. To date, there are three methods of fabricating color centers in silicon carbide: ion injection, electronic irradiation, and femtosecond laser writing. Notably, these methods are too expensive for application. In this work, we use a laser writing method to produce color centers in 4H-SiC, employing a nanosecond laser. The 4H-SiC is placed on a steady optical platform, different powers (from 30 to 100 W) of the laser are used to illuminate the 4H-SiC, and a special array of color centers is produced on different pieces of the 4H-SiC with a size of 4×4 mm. Around the array, several optically-detected color centers appear. The fabricated color centers are optically characterized by confocal imaging with a 532 nm excitation at room temperature. The fluorescence spectra certainly show that the color centers are successfully produced. The Raman spectrum shows approximately 2,000 counts of the color center ensemble. The method clearly results in fabricated silicon vacancy color centers that can emit in both ranges of 850 – 950 nm and 650 – 750 nm. This technique can be used to engineer color centers in SiC for the single-photon generation, sensing, display fabrication, and light emitting diodes.
Point defects in semiconductors are promising single-photon emitters (SPEs) for quantum computing, communication, and sensing applications. However, factors such as emission brightness, purity. and indistinguishability are limited by interactions between localized defect states and the surrounding environment. Therefore, it is important to map the full emission spectrum from each SPE, to understand the complex interplay between the different defect configurations, their surroundings, and external perturbations. Herein, we investigate a family of regularly spaced sharp luminescence peaks appearing in the near-infrared portion of photoluminescence (PL) spectra from n-type 4H-SiC samples after irradiation. This periodic emitter family, labeled the L lines, is only observed when the zero-phonon line signatures of the negatively charged Si vacancy (so-called V lines) are present. The L lines appear with 1.45meV and 1.59meV energy spacing after H and He irradiation and increase linearly in intensity with fluence—reminiscent of the intrinsic defect trend. Furthermore, we monitor the dependence of the L-line emission energy and intensity on heat treatments, electric field strength, and PL collection temperature, discussing these data in the context of the L lines. Based on the strong similarity between the irradiation, electric field, and thermal responses of the L and V lines, the L lines are attributed to the Si vacancy in 4H-SiC. The regular and periodic appearance of the L lines provides strong arguments for a vibronic origin explaining the oscillatory multipeak spectrum. To account for the small energy separation of the L lines, we propose a model based on rotations of distortion surrounding the Si vacancy driven by a dynamic Jahn-Teller effect.
Point defects in semiconductors are emerging as an important contender platform for quantum technology (QT) applications, showing potential for quantum computing, communication, and sensing. Indeed, point defects have been employed as nuclear spins for nanoscale sensing and memory in quantum registers, localized electron spins for quantum bits, and emitters of single photons in quantum communication and cryptography. However, to utilize point defects in semiconductors as single‐photon sources for QT, control over the influence of the surrounding environment on the emission process must be first established. Recent works have revealed strong manipulation of emission energies and intensities via coupling of point defect wavefunctions to external factors such as electric fields, strain and photonic devices. This review presents the state‐of‐the‐art on manipulation, tuning, and control of single‐photon emission from point defects focusing on two leading semiconductor materials—diamond and silicon carbide.
