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Color centers in silicon carbide have increasingly attracted attention in recent years owing to their excellent properties such as single photon emission, good photostability, and long spin coherence time even at room temperature. As compared to diamond which is widely used for

Single-photon emitters (SPEs) play an important role in a number of quantum information tasks such as quantum key distributions. In these protocols, telecom wavelength photons are desired due to their low transmission loss in optical fibers. In this paper, we present a study of bright single-photon emitters in cubic silicon carbide (3C-SiC) emitting in the telecom range. We find that these emitters are photostable and bright at room temperature with a count rate of ~ MHz. Altogether with the fact that SiC is a growth and fabrication-friendly material, our result may be relevant for future applications in quantum communication technology.

Color centers in solids are the fundamental constituents of a plethora of applications such as lasers, light-emitting diodes, and sensors, as well as the foundation of advanced quantum information and communication technologies. Their photoluminescence properties are usually studied under Stokes excitation, in which the emitted photons are at a lower energy than the excitation ones. In this work, we explore the opposite anti-Stokes process, where excitation is performed with lower-energy photons. We report that the process is sufficiently efficient to excite even a single quantum system—namely, the germanium-vacancy center in diamond. Consequently, we leverage the temperature-dependent, phonon-assisted mechanism to realize an all-optical nanoscale thermometry scheme that outperforms any homologous optical method used to date. Our results frame a promising approach for exploring fundamental light-matter interactions in isolated quantum systems and harness it toward the realization of practical nanoscale thermometry and sensing.

An optically stable, room temperature single-photon emitter operating in telecom wavelength range is discovered in GaN.

In this work, we present a method for targeted and maskless fabrication of single silicon vacancy (V Si ) defect arrays in silicon carbide (SiC) using focused ion beam. Firstly, we studied the photoluminescence (PL) spectrum and optically detected magnetic resonance (ODMR) of the generated defect spin ensemble, confirming that the synthesized centers were in the desired defect state. Then we investigated the fluorescence properties of single V Si defects and our measurements indicate the presence of a photostable single photon source. Finally, we find that the Si ++ ion to V Si defect conversion yield increases as the implanted dose decreases. The reliable production of V Si defects in silicon carbide could pave the way for its applications in quantum photonics and quantum information processing. The resolution of implanted V Si defects is limited to a few tens of nanometers, defined by the diameter of the ion beam.Silicon carbide (SiC) is a technologically mature semiconductor material, which can be grown as inch-scale high-quality single crystal wafers and has been widely used in microelectronics systems and high-power electronics, etc. In recent years, some defects in SiC have been successfully implemented as solid state quantum bit 1-8 and quantum photonics 9-11 . They meet essential requirements for spin-based quantum information processing such as optical initialization, readout and microwave control of the spin state, which are similar as the nitrogen vacancy (NV) centers in diamond. 12 In particular, silicon vacancy (V Si ) defect in 4H-SiC has increasingly attracted attention owing to its excellent features, such as non-blinking single photon emission and long spin coherence times which persist up to room temperature (about 160 µs). 3,5,13 These remarkable properties have been exploited in many applications in quantum photonics, 9,10 and quantum metrological studies such as high sensitivity magnetic sensing 14,15 and temperature sensing. 16 The V Si defect consists of a vacancy on a silicon site which exhibits a C 3v symmetry in 4H-SiC. 3,5 In order to extend its applications in quantum information science, it is essential to develop the technique of scalable efficient generation of single V Si defect arays in 4H-SiC. Since the collected fluorescence rate of a single V Si defect is modest with only about 10 kcps, 3,5,17 it is required to couple with some photonic devices to improve the counts towards the construction of photonics networks. 3,9,10,17,20 However, in order to realize the mode-maximum of photonic devices, it is necessary to place the V Si defects relative to the optimal position with sub-wavelength-scale precision. Previously there are three methods to generate V Si defect: the electron irradiation, neutron irradiation, and carbon implantation, however, these methods either can't control the position of the V Si defect, or need a electron beam lithography (EBL) pre-fabricated photoresist patterned mask, 3,5,9,17 which is not convenient for coupling to pre-fabricated photonic devices...

Quantum sensors with solid state electron spins have attracted considerable interest due to their nanoscale spatial resolution. A critical requirement is to suppress the environment noise of the solid state spin sensor. Here we demonstrate a nanoscale thermometer based on silicon carbide (SiC) electron spins. We experimentally demonstrate that the performance of the spin sensor is robust against dephasing due to a self-protected mechanism from the intrinsic transverse electric field of the defect. The SiC thermometry may provide a promising platform for sensing in a noisy environment, e.g. biological system sensing.Nanoscale thermometry has been demonstrated based on various of systems like quantum dot 1,2 , nanoparticle 3,4 , NV (nitrogen vacancy) center spin in diamond 1,6-8 due to its significant benefits to microelectronics and bio-application 910 . Recently, electron spins in silicon carbide have been found to be optically addressable and show superior coherence properties 11,1213 . Besides the favorable features of both CMOS and biocompatibility, sillicon carbide provides a large number of types defects that can be used as candidates for a spin sensor, including PL1-PL6 in 4H-SiC 12 ,QL1-QL6 in 6H-SiC 11 and Ky5 in 3C-SiC 14 . As compared with quantum dot and NV center, nanoscale and highly sensitive thermometry based on a semiconductor material silicon carbide maybe more fascinating because of its versatility in production and widely application in the realm of electronic devices 15 . Moreover, unlike NV center which has 4 possible orientations in bulk diamond 16 , one type of divacancy spins in silicon carbide has the same orientation which improves the sensitivity in varies of sensing application by using an ensemble of divacancy spins.One main challenge for quantum sensors is to improve the sensitivity of quantum metrology against environment noise. Several methods have been developed such as spin echo, dynamical decoupling 17,1819 and quantum error correction 20,21 . These active methods usually make experiments more involved and suffer from certain limitations. In this Letter, we demonstrate high sensitivity temperature sensing based on the electron spins in 4H-SiC divacancies. Especially, the transverse electric field in such defects can suppress the effect of longitudinal magnetic field noise, leading to an improved sensitivity. The self-protected mechanism against decoherence provides an appealing route for scenarios where active methods for suppressing noise may not be suitable.Theory -Here we are considering PL5 defect in SiC 12 , which is a basal C 1h symmetry divacancy showing high optically detected magnetic resonance (ODMR) contrast at room temperature 12 . The ground state shows a spin-1 character with the basis written as {| ↑ , |0 , | ↓ }. The three ground states split at zero magnetic field, resulting in two ODMR resonance spectrum at D + E and D − E. The spin Hamiltonian can be written aswhereFor H 0 term, D(T ) is the temperature-dependence zero field splitting, E x is the transverse el...

With the rapid development of the Internet of Things (IoTs), photovoltaics (PVs) has a vast market supply gap of billion dollars.