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With more than thirty years of research and development until commercialization, performance, reliability, and robustness of silicon carbide (SiC) based devices have been improved significantly due to drastic reduction in crystal defects from the well-controlled processes of crystal growth and device fabrication. It is crucial to investigate the effects of SiC crystal defects on the electrical characteristics of devices. Here, an up-to-date development of the correlation between crystal defects of SiC with electrical performance of the devices has been reviewed. The effect of defects on the electrical parameters of the device and the failure mechanism are discussed, and the development of SiC in recent years is prospected. [ABSTRACT FROM AUTHOR]

The possibility of using axial spin centers with S = 3 / 2 in silicon carbide for all-optical measurement of the projection B z of the external magnetic field onto the c -axis of the SiC crystal, as well as the polar and azimuthal angles of the magnetic field relative to the direction of the c -axis, at room and significantly higher temperatures is shown. Spin centers in SiC, where optically induced spin alignment occurs, have a unique system of spin levels in a magnetic field, caused by the interaction of the fine structure and hyperfine interaction with the 29 Si nuclei. There is a wide range of level anticrossings (LACs) resulting in an extremely strong change in the photoluminescence intensity at LAC. The dependence of the LAC spectrum on the orientation of the external magnetic field is also observed. The proposed magnetometer is based on the compensation of the external magnetic field at the position of the optical excitation spot of the confocal microscope. The sensitivity to a constant magnetic field for the z-component of the magnetic field (B z) is better than 0.1 μ T / Hz in the confocal volume at room temperature. The sensitivity of polar and azimuthal angle determination depends on the sensitivity of the perpendicular component of the magnetic field, which is better than ∼ 0.01 mT / Hz in the range from − 0.4 to 0.4 mT. [ABSTRACT FROM AUTHOR]

Silicon carbide and its derivatives are promising materials with potential applications in various types of nuclear reactors. To better understand their characteristics, this paper investigates the recrystallization behavior of amorphous SiC prepared through pre-irradiation using 800 keV Kr2+. Following different annealing processes, Raman spectra revealed that recrystallization happened beyond 873 K, and nearly complete recrystallization of the amorphous layer occurs at 1423 K. Afterward, in situ annealing and He+ irradiation experiments were conducted. The results indicate that the recrystallization progress is a layer-by-layer epitaxial regrowth on the amorphous–crystal interface under 873 K annealing, and the epitaxial recrystallization would slow down mainly due to the accumulation of defects and Kr atoms. However, under 30 keV He+ irradiation at 873 K, the interface continues to move. Moreover, when the irradiation dose rises, nanocrystals and helium bubbles appear simultaneously, growing in both size and density. The different recrystallization behaviors caused by irradiation and non-irradiation conditions could be explained by radiation-enhanced atomic diffusion, and helium bubbles are likely to be the by-products of nanocrystal formation. A possible explanation is proposed. This study provides insights into the practical application of amorphous silicon carbide in reactors and other irradiation environments. [ABSTRACT FROM AUTHOR]

Silicon/carbon (Si/C) nanocomposites are considered as one of the most promising anode materials for lithium-ion batteries due to their high capacity and suitable lithiation potential. However, the complex and time-consuming preparation processes of silicon-based nanocomposites and the unexpected silicon carbide generated during high treatment make it difficult to achieve high-performance Si/C nanocomposites for practical applications. Herein, a silicon/carbon nanocomposite is successfully prepared through a facile and eco-friendly molten salt assisted precarbonization–reduction method using palygorskite (PAL) and sodium alginate as raw materials. Based on physical characterizations, it is demonstrated that the sodium alginate plays a key role in the successful preparation of Si/C nanocomposite, which not only boosts uniform embedding of PAL nanoparticles in the carbon matrix but also releases molten sodium salt to suppress the formation of unexpected SiC. When used as an alternative anode material for lithium-ion battery applications, the as-obtained Si/C composite delivers a high reversible specific capacity of 1362.7 mA h g−1 with an initial Coulombic efficiency of 70.3% at a current density of 200 mA g−1 and excellent long-term cycling stability. The findings here provide a facile and eco-friendly molten salt assisted precarbonization–reduction method for high-performance silicon/carbon anode materials. [ABSTRACT FROM AUTHOR]

Point defect color centers acting as single-photon emitters are promising for quantum technology applications and have been extensively studied, e.g., in the 4H polytype of silicon carbide (SiC). However, the physics of such color centers in other SiC polytypes is much less explored. Herein, we study the formation and thermal stability of such color centers in 6H-SiC using photoluminescence spectroscopy. The emissions from typical single-photon emitters, such as silicon vacancies, divacancies, and carbon antisite-vacancy pairs in 6H-SiC, were monitored as a function of the proton irradiation fluence and post-irradiation annealing, and compared to that in 4H-SiC. Overall, at the background of similarities between the emission behavior in 4H- and 6H-SiC polytypes, we observed prominent differences; e.g., for the thermal stability of the carbon antisite-vacancy pair, which exhibited maximized emissions upon 300 and 900 ° C anneals in 4H- and 6H-SiC, respectively. Moreover, we observed a range of defect emission signatures not previously reported for 6H-SiC in the literature and discussed their potential origin in the context of the thermal stability. For example, among the PL-lines in 6H-SiC, we detected periodically repeatable emission signatures, resembling the so-called L-lines recently reported in 4H-SiC, even though their exact origin has not yet been settled in the literature. Thus, we use color centers comparison in different polytypes to better understand the nature of the single-photon emitters in SiC. [ABSTRACT FROM AUTHOR]

4H Silicon carbide (SiC) is widely recognized as one of the most advanced wide bandgap semiconductors used in the production of high-efficiency power electronic devices. Impurities play a crucial role in achieving the desired electrical properties in 4H-SiC, yet the understanding of impurities in this material remains limited. In this study, first-principles formation-energy calculations were employed to establish a comprehensive database of formation-energy diagrams for impurities in 4H-SiC. This database includes valuable information on site preference, lattice distortion, solubility, and charge transition levels (CTLs) of the impurities. The site preference for each impurity is closely related to factors such as the Fermi energy, chemical potential, and the impurity species itself. To assess the lattice distortion caused by each impurity, a comparison was made between the volume changes before and after doping. Moreover, the solubility of each impurity was determined using the detailed balance theory, thereby enabling a direct measure of the maximum impurity concentration achievable in the material. Based on the CTLs, the impurities in 4H-SiC were classified into four categories: n-type impurities, p-type impurities, amphoteric impurities, and non-electroactive impurities. This comprehensive property database for impurities in 4H-SiC provides valuable insights for tailoring the material properties through controlled doping, thereby ultimately leading to enhanced performance of power electronic devices. [ABSTRACT FROM AUTHOR]

4H Silicon carbide (4H-SiC) is widely recognized as a highly promising material for high-voltage and high-power electronic applications due to its exceptional properties. The performance of devices based on 4H-SiC is often weakened by the presence of carbon-related point defects, particularly carbon vacancies (VC). The defects of VC introduce deep-level traps (e.g., Z1/2 and EH6/7) that deteriorate device functionality. Experimental and theoretical studies on VC have led to some conflicting results about the charge states of VC, especially for the charge state ordering of EH6/7. We now employ ab initio metadynamics (META) to systematically investigate configuration space including the direction and magnitude of bond distortion and identify the most stable structures of VC. Eventually, the charge states of VC in 4H-SiC are identified. The Z1 (EH6) and Z2 (EH7) indicate transitions from acceptor (donor) levels of VC, located on the h and k sublattice sites, respectively. Z1 and Z2 demonstrate negative-U ordering, characterized by U values of −0.16 and −0.37 eV, respectively. Conversely, EH6 and EH7 display positive-U ordering, with U values of 0.16 and 0.08 eV, respectively. The current results provide insights into the properties of VC in 4H-SiC, highlighting the effectiveness of META in the exploration of complex potential energy surfaces associated with point defects in solids. [ABSTRACT FROM AUTHOR]

Based on the transport and polarization relaxation theories, the effects of hydrogen, fluorine, and chlorine atom passivation on the conductivity and dielectric properties of silicon carbide nanowires (SiCNWs) were numerically simulated. The results show that passivation can decrease the dark conductivity of SiCNWs and increase its ultraviolet photoconductivity. Among them, the photoconductivity of univalent (H) passivated SiCNWs is better than that of seven-valent (Cl, F) passivated SiCNWs. In terms of dielectric properties, the passivated SiCNWs exhibit a strong dielectric response in both deep ultraviolet and microwave regions. Hydrogen passivation SiCNWs produce the strongest dielectric response in deep ultraviolet, while fluorine passivation SiCNWs produce the strongest dielectric relaxation in the microwave band, which indicates that atomic passivation SiCNWs have a wide range of applications in ultraviolet optoelectronic devices and microwave absorption and shielding. [ABSTRACT FROM AUTHOR]

A non-destructive method for detecting sub-micrometer-sized micropipes on an entire wafer surface is investigated. Since it is difficult to detect sub-micrometer-sized micropipes due to their small core size, a non-destructively and accurately detecting method is required. To solve the issue, we focus on a characteristic depression generated around micropipes, namely, line-shaped depressions. In this paper, the location of line-shaped depressions is identified by using optical inspection, and the line-shaped depressions are distinguished whether micropipes exhibit line-shaped depression or not by using mirror electron microscope observation as high-resolution inspection. The accuracy of the distinction results is confirmed by scanning electron microscope observation, and electrical characteristics of the P–N diode are fabricated using the inspected wafer. Furthermore, the sub-micrometer-sized micropipes are observed at the sites of leakage current identified by emission microscopy. Additionally, device simulation of the blocking-voltage characteristics of P–N diodes suggests that the increase in leakage current depends on the electric field at the sub-micrometer-sized micropipes, regardless of their core size. [ABSTRACT FROM AUTHOR]

4H silicon carbide (SiC) polytype is preferred over other SiC polytypes for high-power, high-voltage, and high-frequency applications due to its superior electrical, thermal, and structural characteristics. In this manuscript, we provide a comprehensive study of the spin coupling dynamics between conduction electrons and nitrogen (N) donors in monocrystalline 4H SiC with various concentrations of uncompensated N donors from 1017 to 5 × 1019 cm−3 by continuous wave, pulsed electron paramagnetic resonance (EPR), and microwave perturbation techniques at T = 4.2–300 K. At low temperatures, two triplets due to N donors in cubic (Nk) hexagonal (Nh) positions and triplet arisen from spin-interaction between Nh and Nk were observed in 4H SiC having Nd − Na ≈ 1017 cm−3. A single S-line (S = 1/2) dominates the EPR spectra in all investigated 4H SiC monocrystals at high temperatures. It was established that this line occurs due to the exchange coupling of localized electrons (dominate at low temperatures) and non-localized electrons (dominate at high temperatures). The localized electrons were attributed to Nh for Nd − Na ≈ 1017 cm−3 and Nk donors for Nd − Na ≥ 5 × 1018 cm−3. We have concluded that the conduction electrons in 4H SiC monocrystals are characterized by g|| = 2.0053(3) and g⊥ = 2.0011(3) for Nd − Na ≤ 5 × 1018 cm−3 and g|| = 2.0057(3) and g⊥ = 2.0019(3) for Nd – Na ≈ 5 × 1019 cm−3. Using the theoretical fitting of the temperature variation of S-line EPR linewidth in 4H SiC having Nd – Na ≤ 5 × 1018 cm−3, the energy levels of 57–65 meV that correlate with the valley-orbit splitting values for Nk donors in 4H SiC monocrystals were obtained. [ABSTRACT FROM AUTHOR]

Optically active spin defects in semiconductors can serve as spin-to-photon interfaces, key components in quantum technologies. Silicon carbide (SiC) is a promising host of spin defects thanks to its wide bandgap and well-established crystal growth and device technologies. In this study, we investigated the oxygen-vacancy complexes as potential spin defects in SiC by means of ab initio calculations. We found that the OCVSi defect has a substantially low formation energy compared with its counterpart, OSiVC, regardless of the Fermi level position. The OCVSi defect is stable in its neutral charge state with a high-spin ground state (S = 1) within a wide energy range near the midgap energy. The zero-phonon line (ZPL) of the OCVSi0 defect lies in the near-infrared regime, 1.11–1.24 eV (1004–1117 nm). The radiative lifetime for the ZPL transition of the defect in kk configuration is fairly short (12.5 ns). Furthermore, the estimated Debye–Waller factor for the optical transition is 13.4%, indicating a large weight of ZPL in the photoluminescence spectrum. All together, we conclude that the OCVSi0 defect possesses desirable spin and optical properties and thus is potentially attractive as a quantum bit. [ABSTRACT FROM AUTHOR]

Silicon carbide (SiC) power devices are becoming central components in high voltage electronics. However, defects at interfaces and in the bulk continue to severely impact their reliability and performance. Here, we develop a charge pumping method to characterize SiC/SiO 2 interface defects in fully fabricated commercial SiC power metal–oxide–semiconductor field-effect transistors (MOSFETs). The method is then used to address spin states at the SiC/SiO 2 interface via charge pumping electrically detected magnetic resonance (CP-EDMR). We apply these methods to investigate the power MOSFET after electron irradiation over a dose range of 10 13 − 10 17 cm − 2 . We finally discuss CP-EDMR as a technique to interrogate spins during device operation for real-time monitoring of the device quality, performance, and degradation and as a probe for local magnetic fields. [ABSTRACT FROM AUTHOR]

Switching a silicon carbide (SiC) metal–oxide–semiconductor field-effect transistor between inversion and accumulation with removed drain and grounded source terminals leads to defect-assisted carrier recombination and light emission. The energy spectrum of the emitted photons provides valuable information on the involved defects, located both at the 4H-SiC/ SiO 2 interface and in the 4H-SiC bulk. Here, we measured and analyzed the emitted light over a broad temperature range between 12 and 297 K. Our results reveal two local maxima in light intensity around 30 and 140 K. Most importantly, the local intensity maxima and the related temperatures correlate with both the overall recombination current and gate capacitance measurements. The spectral analysis allowed us to distinguish between recombinations occurring on 4H-SiC bulk defects and 4H-SiC/ SiO 2 interface-related defects. We explain an initial increase of light emission with decreasing temperature to competing non-radiative pathways with activation energies of 34 and 60 meV for SiC/ SiO 2 interface- and 4H-SiC bulk-related emissions, respectively. Based on an extensive literature review, we link the measured photon emission to donor–acceptor pair recombination, the EH 6 / 7 or the Z 1 / 2 defect centers. In addition to that, we could link a prominent peak at 2.915 eV to the L 1 line of the D 1 -center. Most importantly, we conducted our own ab initio simulations revealing that recombination via P bC -centers, previously identified with carbon dangling bonds at the 4H-SiC/ SiO 2 interface [Cottom et al., J. Appl. Phys. 124, 045302 (2018)], could also provide an explanation for the photon emission around 1.75 eV. Finally, our simulation of an interface-related silicon vacancy V Si , I reveals a radiative transition around 2.8 eV. [ABSTRACT FROM AUTHOR]

Stacking faults in silicon carbide have been widely studied due to their negative impact on the application of silicon carbide in the power electronics industry. In this work, with the assistance of forward biasing, we observe several triangular shaped structures emerging near the indenter imprint in two separate 4H–SiC bipolar junction transistor samples that were deformed by nanoindentation. Based on the study of electroluminescence spectra on one of the samples, the emission peak at 420 nm indicates the formation of single Shockley stacking faults inside deformed transistors. We conclude that the use of indentation can provide a method to study recombination induced stacking faults in silicon carbide junction devices by intentionally introducing dislocations at selected areas of interest. [ABSTRACT FROM AUTHOR]

Phonon-polaritons are known to emerge at the surface of solids under infrared (IR) irradiation at frequencies close to the optical phonon resonance. Metal, patterned on the top of the polariton-active surface, locally blocks the excitation of surface waves due to plasmonic screening and can be used for the design of wave patterns. We excite polaritonic waves at the surface of SiC under the irradiation of a CO2 laser (λ ∼ 10 μ m) and visualize them using apertureless near-field interference scanning probe microscopy. From the near-field scans in the vicinity of gold film periodical strip structures, we identify the Bragg scattering (diffraction) outside the grating with the contribution from separate strips coherently summed up, provided that the wavelength matching condition is fulfilled. The observed phenomena agree with wavefield calculations. Our observations demonstrate the potential of metal-patterned silicon carbide for the fabrication of on-chip polaritonic IR circuits. [ABSTRACT FROM AUTHOR]

Epitaxial graphene (EG) on cubic silicon carbide (3C-SiC) on silicon holds the promise of tunable nanoelectronic and nanophotonic devices, some uniquely unlocked by the graphene/cubic silicon carbide combination, directly integrated with the current well-established silicon technologies. Yet, the development of graphene field-effect devices based on the 3C-SiC/Si substrate system has been historically hindered by poor graphene quality and coverage, as well as substantial leakage issues of the heteroepitaxial system. We address these issues by growing EG on 3C-SiC on highly resistive silicon substrates using an alloy-mediated approach. In this work, we demonstrate a field-effect transistor based on EG/3C-SiC/Si with gate leakage current 6 orders of magnitude lower than the drain current at room temperature, which is a vast improvement on the current literature, opening the possibility for dynamically tunable nanoelectronic and nanophotonic devices on silicon at the wafer level. [ABSTRACT FROM AUTHOR]

We investigate the crack-healing mechanism of 4H silicon carbide (4H-SiC) and reveal the effect of dopants on the crack-healing behavior of 4H-SiC. Vickers indentation tests and thermal annealing are utilized to generate cracks and heal cracks in 4H-SiC, respectively. High-temperature thermal annealing in the air atmosphere is found to be capable of effectively healing indentation-induced cracks and releasing indentation-induced stress in undoped 4H-SiC by the formation and viscous flow of glass phase SiO2. Nitrogen (N) doping is found to assist the atomic diffusion of 4H-SiC. The crack healing of N-doped 4H-SiC is realized by the synergy of host solid diffusion and the padding of glassy SiO2. In contrast, vanadium (V) doping hinders the viscous flow of SiO2 and results in the incomplete healing of cracks in V-doped 4H-SiC. Although the generation of cracks lowers the bending strength of 4H-SiC, the healing of cracks by the padding of glassy SiO2 is found to effectively recover the bending strength of indented 4H-SiC samples. Our work opens a pathway to design thermal processing technologies to heal the cracks and enhance the mechanical properties of 4H-SiC wafers. [ABSTRACT FROM AUTHOR]

Pulsed lasers are a powerful tool for fabricating silicon carbide (SiC) that has a hard and brittle nature, but oxidation is usually unavoidable. This study presents an exploration of the oxidation mechanism of 4H–SiC in oxygen and water under different temperatures via reactive force field molecular dynamics. Single pulse irradiation experiments were conducted to study the oxygen content of the laser-affected zone through energy dispersive x-ray spectrometry. The results show that laser-induced thermal oxidation is a complex dynamic process with the interactions among H, C, O, and Si atoms. The oxidation zone includes an oxide layer, a graphite layer, and a C-rich layer. With an increase in oxygen concentration, the amorphous oxide layer changes from silicon oxide to silicon dioxide. In addition, the formation of carbon clusters at the interface between SiOx and C-rich layers promotes the desorption of the oxide layer. The mechanism revealed in this study provides theoretical guidance for high-quality processing of 4H–SiC at atomic and close-to-atomic scales. [ABSTRACT FROM AUTHOR]

In most optical waveguides employed within photonic integrated circuits, light confinement is achieved by etching the high-index layer. However, these waveguides often lack versatility in optimizing optical properties, such as mode size, shape, dispersion, and polarization. Moreover, they frequently suffer from high coupling losses and their propagation losses are significantly influenced by the quality of the etching process, especially for materials with high mechanical rigidity. Here, we present a hybrid optical waveguide concept that effectively addresses these limitations by combining a strip of easily processible low-index material (SU8) with a high-index hard-to-etch guiding layer (amorphous silicon carbide, SiC). Our approach not only eliminates the need for SiC etching but also offers flexibility in waveguide design to accommodate advanced functionalities. One of the key advancements of this hybrid configuration is its ability to suppress the transverse magnetic mode by 62 dB at 1550 nm, effectively functioning as a transverse electric pass waveguide. This simplifies the measurements by eliminating the need for polarization controllers and polarizers. Furthermore, through tailored waveguides, we achieve 2.5 times higher coupling efficiency compared to untapered hybrid SiC waveguides. We also demonstrate that thermal baking of the polymer layer reduces the scattering losses from 1.57 to 1.3 dB/cm. In essence, our hybrid approach offers a versatile way of realizing low-loss SiC-based integrated optical components with advanced features, such as excellent polarization suppression, flexible mode shapes, and dispersion control, compared to etched counterparts. [ABSTRACT FROM AUTHOR]

This research explores into analyzing the mechanical characteristics of banana fiber and ramie fiber composites bolstered with silicon carbide (SiC) nanoparticles. The integration of SiC nanoparticles aims to amplify the mechanical robustness and endurance of these natural fiber composites. Through water absorption assessments, we evaluated the composites' resistance to moisture. In addition, we assessed the mechanical performance via hardness, impact, and three-point bending tests. The results indicate a significant enhancement in the mechanical attributes of both banana and ramie fiber composites due to SiC nanoparticle inclusion. The results reveal a notable enhancement in mechanical characteristics following the incorporation of SiC nanoparticles. Notably, composites containing 8% SiC nanoparticles demonstrated the highest hardness value of 102 HV and the lowest water absorption percentage of 1.5%. In addition, these composites exhibited a superior flexural strength (80 MPa) and modulus of elasticity (4.3 GPa), alongside a maximum impact energy absorption of 18 J. These findings underscore the beneficial influence of SiC nanoparticles on the mechanical properties of the composites, including increased strength, reduced water absorption, enhanced hardness, and improved impact resistance. [ABSTRACT FROM AUTHOR]

The interfacial electrical properties of deposited oxide (SiO2) onto cubic silicon carbide (3C-SiC) were investigated after different post-oxide deposition annealing (PDA) by means of metal–oxide–semiconductor (MOS) capacitors and nanoscale capacitance mapping. The deposited oxides subjected to PDA at 450 °C in either nitrogen or forming gas showed a reduction of the interface and oxide traps, as well as an improved oxide field strength compared to the thermally grown insulating layer. Spatially resolved nanoscale capacitance mapping performed onto the oxide surface revealed that the density of the electrically active stacking faults (SFs) in 3C-SiC is diminished by appropriate PDA. The results pave the way to obtain an ideal SiO2/3C-SiC system suitable for power device applications. [ABSTRACT FROM AUTHOR]

High-purity semi-insulating (HPSI) 4H silicon carbide (4H-SiC) single crystals are critical semiconductor materials for fabricating GaN-based high-frequency devices. One of the major challenges for the growth of HPSI 4H-SiC single crystals is the unintentional doping of nitrogen (N) and boron (B). The addition of hydrogen has been supposed to mitigate unintentional doping. However, the underlying mechanism has not been well understood. In this work, the role of hydrogen in the growth of HPSI 4H-SiC single crystals is investigated by first-principles formation-energy calculations. We find that the addition of hydrogen significantly mitigates N doping while hardly affecting B doping. Once hydrogen is added, hydrogen may adsorb at the growing surface of 4H-SiC, leading to surface passivation. Since N can react with hydrogen to form stable NH3 (g), the chemical potential of N is reduced, so that the formation energy of N in 4H-SiC increases. Hence, the critical partial pressure of nitrogen required for the growth of HPSI 4H-SiC single crystals increases by two orders of magnitude. Moreover, we reveal that the adjustment of relative B and N doping concentrations has a substantial impact on the Fermi energy of HPSI 4H-SiC. When the doping concentration of N is higher than that of B, N interacts with carbon vacancies (VC) to pin the Fermi energy at Z1/2. When the doping concentration of B is higher than that of N, the Fermi energy is pinned at EH6/7. This explains that the resistivity of unintentionally doped HPSI 4H-SiC may vary. [ABSTRACT FROM AUTHOR]

The formation mechanism of half-loop arrays (HLAs) that form parallel (horizontal) to the step-flow direction in 120 μm thick 4H-silicon carbide (SiC) epitaxial layers was investigated using ultraviolet photoluminescence (UVPL) imaging and x-ray topography (XRT). The horizontal-HLAs are generated by the multiplication and glide of basal plane dislocation (BPD) loops that are created within the epitaxial layer. The BPD loops were initiated after ∼40–50 μm of growth from a small BPD segment, which glides toward the surface as well as the substrate interface. BPD multiplication occurs and several loops are generated. Some of these loops are terminated by the growth front and create HLAs due to the 4° offcut of the wafer. XRT images show that successive BPD loops interact with previously generated HLA segments. Successive loops also interact with the moving growth front and create new HLAs that are spatially displaced from the previous HLA segments. These appear as a string of horizontal-HLAs in the UVPL images. The expansion of stacking faults (SFs) from these horizontal-HLAs was investigated, and we show that they all lie on the same basal plane. The complex defect structure is created in the epitaxial layer from a single BPD loop but extends over a large (∼5 × 0.5 cm2) region of the SiC wafer during epitaxial growth. The high density of HLAs and BPDs would generate several SFs upon device operation leading to severe device degradation. [ABSTRACT FROM AUTHOR]

Detonation synthesis of silicon carbide (SiC) nanoparticles from carbon liberated by negatively oxygen balanced explosives was evaluated in a 23 factorial design to determine the effects of three categorical experimental factors: (1) cyclotrimethylene-trinitramine (RDX)/2,4,6-trinitrotoluene (TNT) ratio, (2) silicon (Si) additive concentration, and (3) Si particle size. These factors were evaluated at low and high levels as they relate to the detonation performance of the explosive and the solid Si-containing phases produced. Detonation velocity and Chapman-Jouguet (C-J) detonation pressure, which were measured using rate stick plate dent tests, were evaluated. Solid detonation product mass, silicon carbide product concentration, and residual silicon concentration were evaluated using the x-ray diffraction analysis. The factors of Si concentration and the RDX:TNT ratio were shown to affect detonation performance in terms of detonation velocity and C-J pressure by up to 10% and 22%, respectively. Increased concentration of Si in the reactants improved the average SiC concentration in the detonation products from 1.9 to 2.8 wt.%. Similarly, increasing the ratio of RDX to TNT further oxidized detonation products and reduced the average residual Si remaining after detonation from 8.6 to 2.8 wt.%. A 70:30 mass ratio mixture of RDX to TNT loaded with 10 wt.%< 44 µm silicon powder produced an estimated 1.33 g of nanocrystalline cubic silicon carbide from a 150-g test charge. Using a lower concentration of added silicon with a finer particle size reduced SiC yield in the residue to 0.38 g yet improved the SiC to residual Si ratio to 1.64:1. [ABSTRACT FROM AUTHOR]

We present two compact ultrafast electron injector designs with integrated focusing that provide high peak brightness of up to 1.9 × 1012 A/m2 Sr2 with 10's of electrons per laser pulse using silicon carbide electrodes and silicon nanotip emitters. We demonstrate a few centimeter scale 96 keV immersion lens electron source and a 57 keV immersion lens electron source with a 19 kV/mm average acceleration gradient, nearly double the typical 10 kV/mm used in DC electron sources. The brightness of the electron sources is measured alongside start-to-end simulations including space charge effects. These sources are suitable for dielectric laser accelerator experiments, ultrafast electron diffraction, and other applications, where a compact high brightness electron source is required. [ABSTRACT FROM AUTHOR]

Color centers in wide bandgap semiconductors are prominent candidates for solid-state quantum technologies due to their attractive properties including optical interfacing, long coherence times, and spin–photon and spin–spin entanglement, as well as the potential for scalability. Silicon carbide color centers integrated into photonic devices span a wide range of applications in quantum information processing in a material platform with quantum-grade wafer availability and advanced processing capabilities. Recent progress in emitter generation and characterization, nanofabrication, device design, and quantum optical studies has amplified the scientific interest in this platform. We provide a conceptual and quantitative analysis of the role of silicon carbide integrated photonics in three key application areas: quantum networking, simulation, and computing. [ABSTRACT FROM AUTHOR]

Significant progress has been achieved with silicon carbide (SiC) high power electronics and quantum technologies, both drawing upon the unique properties of this material. In this Perspective, we briefly review some of the main defect characterization techniques that have enabled breakthroughs in these fields. We consider how key data have been collected, interpreted, and used to enhance the application of SiC. Although these fields largely rely on separate techniques, they have similar aims for the material quality and we identify ways in which the electronics and quantum technology fields can further interact for mutual benefit. [ABSTRACT FROM AUTHOR]

Strain provides an additional mechanism in tuning the thermal/electrical properties of nanostructures and therefore has triggered lots of interest in recent years. However, experimental research about the strain effect on the thermal conductivity of nanowires is still limited, especially in the low-temperature range, which is important in understanding the physics of strain-induced regulation in thermal conductivity. Here, we present thermal transport measurements of bent silicon carbide nanowires at temperatures ranging from 20 to 300 K. Reduction in thermal conductivity compared to their straight counterparts is observed. More specifically, the relative change is up to 55% at 20 K and descends with temperature, which is due to the inhomogeneous strain-induced phonon scattering. This study will deepen the understanding of thermal properties in nanostructures with strain. [ABSTRACT FROM AUTHOR]

In this article, we present a transient temperature detection device for silicon carbide (SiC) Schottky barrier diodes (SBDs) based on thermal reflection theory. We constructed a thermal reflection temperature measurement device based on a 530-nm green laser. This device is more suitable for transient temperature measurement of SiC SBDs than previous thermal reflection equipment. The accuracy of temperature measurement by our device was confirmed by comparison with the results of infrared thermal imaging. The high temporal resolution characteristics of the thermal reflection technology allowed the detection of millisecond-level transient temperature changes in SiC SBDs. In addition, we investigated the complementarity of transient temperature change curves during heating and cooling processes, as well as the reasons for the differences between these curves. Finally, we used the structural function method combined with the Bayesian deconvolution algorithm to obtain the thermal resistance along the heat flow path of the device and validated the results using an established thermal resistance testing method. [ABSTRACT FROM AUTHOR]

Silicon carbide ceramic membranes are known as a new generation of membrane products due to their excellent chemical stability and high flux advantages. This article, based on the PatSnap patent analysis, analyzes the global patents of silicon carbide ceramic membranes, preparation methods, devices and equipment, application-related patents, and applicants from perspectives of patent applications, patent layouts, and international patent classification technical categories. It concludes that the technological hotspots in the field of silicon carbide ceramic membranes are concentrated on improving separation efficiency through separation applications, providing a reference for the technical improvement, application, and patent layout of silicon carbide ceramic membranes. [ABSTRACT FROM AUTHOR]

Electromagnetically induced transparency (EIT) is a phenomenon that can provide strong and robust interfacing between optical signals and quantum coherence of electronic spins. In its archetypical form, mainly explored with atomic media, it uses a (near-)homogeneous ensemble of three-level systems, in which two low-energy spin-1/2 levels are coupled to a common optically excited state. We investigate the implementation of EIT with c-axis divacancy color centers in silicon carbide. While this material has attractive properties for quantum device technologies with near-IR optics, implementing EIT is complicated by the inhomogeneous broadening of the optical transitions throughout the ensemble and the presence of multiple ground-state levels. These may lead to darkening of the ensemble upon resonant optical excitation. Here, we show that EIT can be established with high visibility also in this material platform upon careful design of the measurement geometry. Comparison of our experimental results with a model based on the Lindblad equations indicates that we can create coherences between different sets of two levels all-optically in these systems, with potential impact for RF-free quantum sensing applications. Our work provides an understanding of EIT in multi-level systems with significant inhomogeneities, and our considerations are valid for a wide array of defects in semiconductors. [ABSTRACT FROM AUTHOR]

The divacancy in silicon carbide (SiC) is a prominent solid state defect quantum bit that bears a relatively strong fluorescence and optically detected magnetic resonance contrast (ODMR) at room temperature. These properties exemplify it for quantum sensing of biological molecules. To this end, we previously developed a top-down method to create divacancies in cubic SiC nanoparticles (NPs) as non-perturbative ODMR biomarkers. In this process, large SiC particles are synthesized and then stain etched to form porous SiC and then ultrasonication and filtering are applied to the solution to extract few nanometer diameter SiC NPs. We called this process no-photon exciton generation chemistry (NPEGEC). We showed that by adding aluminum to carbon and silicon in the synthesis process of cubic SiC, one can engineer divacancy defects in SiC NPs by NPEGEC. An alternative traditional way to introduce vacancies to the SiC lattice is irradiation. Here, we compare the fluorescence spectra of divacancies as created by neutron irradiation in porous cubic SiC and NPEGEC technique in SiC NPs, and the results are analyzed in detail by means of first principles calculations. We find that the irradiation technique produces a larger shift in the fluorescence spectrum with residual background fluorescence than that for divacancies in SiC NPs, which is most likely caused by the parasitic defects left after irradiation and annealing in the former sample. These results imply that the chemistry technique applied to prepare divacancies in few nanometer SiC NPs may preserve the bulk-like quality of divacancy quantum bits near the surface. [ABSTRACT FROM AUTHOR]

We use a dielectric response theory to describe electrodynamic forces on a charged particle moving parallel to a supported two-dimensional layer. Using a Kramers–Kronig relation, we show that the image force on the particle can be expressed in terms of the energy loss function of the target materials. This enables us to analyze the stopping and the image forces on the particle on equal footing in the frequency–momentum domain encompassing all the energy loss channels in the target. Using the example of a graphene layer on a silicon carbide substrate, we show that both the image and stopping forces can be decomposed into contributions coming from two modes arising from hybridization of the sheet plasmon in doped graphene and a transverse optical phonon in the substrate. [ABSTRACT FROM AUTHOR]