Search Results (2,230)

Background: The optical losses in the form of reflections, parasitic absorption, and scattering limit photovoltaic efficiency. This review examines plasma-assisted surface engineering as an effective tool for improving light management in solar cells. Plasma-based methods, including etching, oxidation, deposition, and texturing, enable precise control of surface morphology and chemistry, lowering reflectance, enhancing light trapping, and passivating defects. Methods: In contrast to wet-chemical or high-temperature processes, plasma processes are dry, low-temperature, scalable, and can be used with silicon, perovskite, thin-film, and organic solar cells, as well as tandem structures. The fundamentals of optical losses are described, along with the principles of radio-frequency (RF), inductively coupled plasma (ICP), microwave, and atmospheric plasma systems and their distinctive advantages for controlling ion and reactive-species generation. Key applications reviewed include black-silicon texturing by ICP reactive-ion etching (ICP-RIE), anti-reflective/passivation coatings by plasma-enhanced chemical vapor deposition (PECVD), and interface activation by atmospheric plasma. Results: Among performance improvements are a reflectance of less than 2%, a photocurrent increase of 10–20%, and longer carrier lifetime. Conclusions: The advantages of plasma compared to lithography and sol–gel processes are in the precision and affordability of the method. The difficulties include damage caused by the processing, uniformity over extensive areas, and environmental stress resistance. Future directions rely on low-temperature plasmas for flexible PV, machine-learning-guided process optimization, and hybrid plasma–laser systems. This synthesis of otherwise fragmented studies is intended to support the implementation of plasma-based methods in next-generation, high-efficiency, and sustainable solar production. Full article

This study investigates the formation and evolution of nitrogen-vacancy (NV) centers in nitrogen-doped CVD diamonds. The diamonds were grown via the microwave plasma-assisted chemical vapor deposition (MPACVD) method with different levels of nitrogen doping, then irradiated with helium and hydrogen ions at different energies and doses, followed by low-pressure, high-temperature (LPHT) annealing at 1300 °C and 1400 °C. The presence and intensity of NV⁰ and NV⁻ centers were identified and tracked by photoluminescence spectroscopy after each step. The results showed that both helium and hydrogen irradiation could induce NV center formation, with variation in NV⁰/NV⁻ charge states depending on the irradiation conditions. Helium-irradiated samples generally exhibited stronger NV⁻ signatures; however, the hydrogen-irradiated sample 5N10 (3 MeV, 1 × 10¹³ ions/cm²) displayed the most pronounced NV⁻ presence of all samples, highlighting the critical role of nitrogen content and irradiation parameters. Ion irradiation reduced internal hydrostatic stress in all samples—from up to +0.23 GPa (compressive) in N5 and down to −0.82 GPa (tensile) in N10—relaxing stress toward near-zero values while increasing the Raman FWHM from ~3.5 cm⁻¹ to up to 6.7 cm⁻¹, indicating lattice disorder. LPHT annealing at 1300–1400 °C significantly increased NV-related photoluminescence, indicating effective thermal activation of vacancy-nitrogen recombination. Complementary Raman and FTIR analyses were employed to assess stress and defect evolution. The methodology enabled a comprehensive evaluation of the effects of irradiation and annealing on diamond defect structures, providing relevant experimental data for the controlled engineering of NV centers for quantum technologies. Full article

Two-dimensional transition metal dichalcogenides (TMDCs) hold great promise for next-generation optoelectronics. However, the low photoluminescence (PL) quantum yield due to inevitable defects during material preparation severely restricts their practical application. Here, we report a rational defect-engineering strategy based on first-principles calculations and realize it experimentally on MoS₂ monolayers by doping with calcium atoms. First-principles calculations reveal that proper doping can introduce complementary defect levels to effectively tailor carrier dynamics. Guided by this theoretical design, we synthesized calcium-doped MoS₂ monolayers via one-step chemical vapor deposition. The as-grown doped MoS₂ flakes reach sub-millimeter scale (~568 μm). Compared with undoped samples, the Ca-doped MoS₂ exhibits two orders of magnitude PL enhancement, significantly prolonged carrier lifetime, and efficient conversion from negative trions to neutral excitons. This strategy is also applicable to other alkaline earth dopants, providing a generalizable route for defect engineering in two-dimensional semiconductors. Full article

Non-layered two-dimensional (2D) chromium-based chalcogenides have garnered significant attention due to their distinctive magnetic, electronic, and optical properties. In this work, we report the controllable synthesis of high-quality rhombohedral Cr₂S₃ nanosheets on mica substrates via an atmospheric pressure chemical vapor deposition (CVD) strategy. The as-grown rhombohedral Cr₂S₃ nanosheets exhibit pronounced optical second-harmonic generation (SHG) signals, which show thickness-dependent enhancement and a strong dependence on both the linear excitation and detection polarization configurations. Most notably, temperature-dependent SHG measurements reveal a distinct inflection point near the Néel temperature (T_N ≈ 120 K), where the SHG intensity exhibits a sharp enhancement upon cooling below T_N. This behavior arises from the additional magnetic dipole contributions activated by magnetic ordering, establishing SHG as a sensitive probe of magnetic phase transitions in non-layered 2D magnetic materials. Furthermore, circularly polarized SHG signals exhibit nearly 100% circular polarization at low temperatures. This work systematically elucidates the nonlinear optical response characteristics of rhombohedral Cr₂S₃ and their correlation with magnetic ordering transitions, laying an experimental foundation for the application of 2D non-van der Waals magnetic materials in nonlinear optoelectronics and spin-optoelectronic devices. Full article

Aluminum and its alloys feature low weight and high strength. They are widely applied in aerospace, automobile manufacturing, and marine engineering. However, they are highly susceptible to localized corrosion. Such defects can severely restrict the service life of the substrate materials. Pristine graphene exhibits atomic-level compact impermeability, stable chemical inertness, and excellent mechanical properties. It is a promising candidate material for the protection of aluminum substrates. Nevertheless, an electrically insulating interlayer is generally required between pristine graphene and aluminum to achieve reliable protection. This measure avoids the risk of galvanic corrosion. This paper systematically reviews the latest research progress of graphene-based coatings on aluminum, focusing on pristine graphene, graphene oxide (GO), reduced graphene oxide (rGO), and graphene-polymer composite coatings. It focuses on the preparation methods and corrosion protection performance of the materials. This study compares various mainstream preparation technologies in detail. The technologies include chemical vapor deposition, electrochemical deposition, mechanical exfoliation, solution coating, laser induction, and thermal spraying. The corrosion protection mechanism is discussed from three dimensions. The dimensions include physical barrier effect, tortuous path mechanism, and electrochemical protection. Key influencing factors, such as coating defects and environmental conditions, are also investigated. This paper summarizes the application potential of graphene-based coated aluminum in high-end manufacturing fields. It points out the major existing challenges of the material. The challenges involve coating uniformity, adhesion strength, long-term stability, and industrial production. Finally, future research directions are proposed in this work. These directions include the development of innovative coating technologies, the construction of composite protection systems, the design of intelligent self-healing functions, and the exploration of environmentally friendly preparation processes. Full article

Titanium and its alloys are widely used in cardiovascular devices because of their favorable mechanical properties, corrosion resistance, and biocompatibility. Nevertheless, their surfaces do not fully prevent nonspecific protein adsorption, platelet activation, thrombosis, bacterial colonization, or long-term degradation under physiological conditions. Silicon-nitride-based (SiN_x) coatings represent a promising strategy for addressing these limitations by combining chemical stability, mechanical durability, hemocompatibility, and antibacterial activity. This review critically examines silicon-nitride-based (SiN_x) coatings on titanium for cardiovascular applications, focusing on deposition technologies, interfacial phenomena, surface characteristics, and biological performance. Particular attention is given to physical vapor deposition parameters, coating adhesion, residual stresses, interfacial reactions, corrosion resistance, and mechanical stability. Relationships between surface chemistry, wettability, protein adsorption, platelet response, hemolysis, and cellular behavior are discussed, alongside the effects of static and dynamic testing conditions. SiN_x is also compared with Au, TiN, TiO₂, ZrN, and silicon carbide-based coatings. Despite encouraging in vitro results, clinical translation remains limited by insufficient standardization, scarce long-term and flow-dependent data, and an incomplete understanding of degradation mechanisms. Future studies should integrate interface engineering with microfluidic models, standardized hemocompatibility testing, artificial intelligence-assisted optimization of process–structure–property–biological response relationships, and regulatory considerations to support the safe clinical translation of SiN_x-coated cardiovascular devices. Full article

Harsh-environment pressure sensing requires piezoelectric materials that can simultaneously withstand elevated temperature, mechanical loading, and structural degradation. GaN is a promising lead-free piezoelectric semiconductor owing to its wide bandgap, high thermal stability, and non-centrosymmetric wurtzite structure. However, its piezoelectric output can be significantly affected by free-carrier compensation in unintentionally n-type GaN. Here, we report a flexible all-inorganic piezoelectric pressure sensor based on a directly grown h-BN/GaN heterostructure thin film. The h-BN layer was deposited on GaN/Si by plasma-enhanced chemical vapor deposition, followed by backside Si removal, electrode deposition, and transfer onto a flexible Cu foil substrate. Structural characterizations confirmed the formation of a compact h-BN/GaN interface with clear lattice fringes, preferential out-of-plane orientation, and characteristic Raman signatures of both h-BN and GaN. Compared with the flexible GaN/Cu reference, the h-BN/GaN device exhibits modified interfacial electrical transport behavior, enhanced voltage and current-density outputs, and prolonged transient voltage retention. Finite-element simulations reveal modified electrostatic potential distribution after h-BN integration, while electrical and interfacial characterizations suggest electronic structure modulation and reduced carrier compensation effects at the heterointerface. Raman optothermal analysis indicates an improved relative/local thermal response of the h-BN/GaN device under identical optical excitation conditions, supporting its enhanced thermal robustness. Under 200 psi at 400 °C, the h-BN/GaN sensor maintains an output voltage of approximately 27.65 mV, about 2.32 times that of the GaN reference. This work demonstrates an interfacial engineering strategy based on two-dimensional h-BN integration for constructing flexible, thermally robust, and high-output piezoelectric sensors for harsh-environment monitoring. Full article

In this work, boron incorporation in diamond grown by microwave plasma-enhanced chemical vapor deposition is investigated as a function of methane concentration, boron precursor concentration, crystalline orientation, oxygen addition to the plasma, and deposition temperature. The boron incorporation efficiency, i.e., the ratio between the boron concentration in diamond and the gas-phase boron-to-carbon ratio, spans several orders of magnitude and can exceed unity for all investigated crystalline orientations. Overall results demonstrate that methane concentration and the substrate’s crystalline orientation are key factors governing boron incorporation. The temperature study reveals that boron incorporation is also governed by thermally activated boron-loss mechanisms. Finally, all results show that boron incorporation is not exclusively controlled by the plasma composition but also by surface growth mechanisms. Full article

Aerosol-assisted chemical vapor deposition (AACVD) was used to prepare a thin film of the heterojunction MnO₂/WO₃ onto an FTO glass substrate. The WO₃/MnO₂ heterojunction thin film exhibited a monoclinic WO₃ structure characterized by a nanorod-like shape and substantial interfacial bonding. The detected surface area of the WO₃/MnO₂ thin film is 32.58 ± 0.79 μm², while the values of R_a and R_q are 23.20 ± 2.26 nm and 29.60 ± 2.40 nm, respectively, which are higher than pure MnO₂ (R_a =13.40 ± 0.99 nm), while lower than pure WO₃ (R_a = 69.75 ± 1.34 nm) thin films. The UV–Vis spectra demonstrated extensive absorption in the visible to near-infrared range. The absorption spectrum of UV–Vis (200–900 nm) displayed a distinct absorption edge under 400 nm. The band gap of the pure WO₃ thin film equals 2.79 eV, whereas an effective band gap of WO₃/MnO₂ was observed to equal 1.51 eV, which is significantly smaller than that of the individual oxides (MnO₂ = 4.47 eV and WO₃ = 2.79 eV). Photoluminescence (PL) verified the robust interfacial electronic interaction. The investigation of the PEC performance exhibited the best performance and the greatest photocurrent under illumination than either pure component. Additionally, there was a good enhancement and improvement in the charge separation due to combining the catalytic MnO₂ thin film with a photoactive WO₃, owing to its effective charge transfer and decreased recombination. Full article

Glass fiber-reinforced plastics (GFRPs) rely on strong fiber–matrix adhesion to achieve optimal mechanical performance. However, conventional sizing systems provide only partial surface coverage and may limit interfacial bonding. The current study investigates atmospheric-pressure plasma-enhanced chemical vapor deposition (APECVD) as an alternative approach for depositing adhesion-promoting plasma coatings on glass fibers intended for epoxy-based composites. Organosilane precursors were deposited using an atmospheric plasma jet under different operating conditions, and the chemical composition and the morphology of the resulting plasma coatings were extensively characterized. Adhesion performance was evaluated by pull-off tests on glass sheets and pull-out tests on glass fibers embedded in epoxy resin. Results show that the plasma coatings provide complete surface coverage and present a tunable chemistry containing several adhesion-promoting functional groups, including silanol and amine-containing species. Pull-off tests on glass sheets demonstrate adhesion improvements of at least 68% compared with untreated glass. In pull-out tests, plasma-coated glass fibers achieved interfacial shear strengths up to 102.9% higher than untreated fibers and 24.4% higher than an industrial reference material. These results demonstrate how atmospheric plasma polymerization can produce effective adhesion-promoting coatings on glass surfaces, thus offering a promising and industrially scalable alternative to conventional adhesion promoters for epoxy-based GFRPs. Full article

Two-dimensional GaS_xTe_1−x alloy nanosheets with different compositions were synthesized by chemical vapor deposition using GaS and GaTe powders as precursors. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) analyses confirmed their sheet-like morphology and the uniform distribution of S and Te, while Raman and photoluminescence measurements revealed composition-dependent vibrational and emission characteristics. Te-rich samples exhibited position-dependent emission ranging from the red to the near-infrared region, whereas increasing the S content gradually shifted the emission toward the blue-green region. Among the synthesized samples, GaS_0.9Te_0.1 showed a relatively stable photoluminescence peak near 520 nm and was therefore selected as a fluorescent powder for latent fingermark development. Its performance was evaluated on glass, stainless steel, plastic, and ceramic surfaces and compared with that of silver powder, gold powder, and commercial red fluorescent powder. GaS_0.9Te_0.1 produced clear fluorescent ridge patterns and strong background contrast, particularly on glass, plastic, and white ceramic. The mean contrast across the four substrates reached 25.83, exceeding that of the reference powders. These results demonstrate that GaS_xTe_1−x nanosheets possess tunable optical properties and that GaS_0.9Te_0.1 is a promising fluorescent material for latent fingermark development on non-porous surfaces. Full article

Two-dimensional indium selenide (InSe) is a promising material for next-generation electronics, characterized by a small electron effective mass and ultrahigh room-temperature mobility. This review systematically examines the fundamental physics and emerging quantum phenomena intrinsic to InSe. It also addresses the recent discovery of sliding ferroelectricity, which breaks macroscopic spatial inversion symmetry and yields robust polarization states without conventional displacive ionic dynamics. Technological progress from mechanical exfoliation to scalable bottom-up metal–organic chemical vapor deposition is evaluated. The review also covers advanced architecture enabled by InSe, including sub-3 nm-node logic transistors and nonvolatile ferroelectric synaptic devices. Finally, key challenges involving stoichiometric control, back-end-of-line-compatible integration, and environmental instability are discussed in the context of future low-power and neuromorphic computing. Full article

In this paper, a 2.5 nm thick Al₂O₃ interlayer deposited by atomic layer deposition was inserted between AlGaN/GaN HEMT structure and SiN_x passivation layer to reduce interface damage of the semiconductor/dielectric introduced directly by plasma-enhanced chemical vapor deposition. It is found that this ultra-thin Al₂O₃ interlayer can not only obviously increase the output current and extrinsic transconductance by reducing the access-region resistance, but also effectively suppress current collapse and the threshold voltage drift due to fewer interface defects in the access region between the gate and drain. More importantly, dynamic on-resistance degradation of devices with an Al₂O₃ interlayer is significantly improved in comparison with the only Si₃N₄-passivated HEMTs without an Al₂O₃ interlayer. Full article

We present a brief review that highlights the importance of III-Nitride semiconductor compounds according to their structural, compositional, morphological, and optical properties, which have significant applications in new semiconductor devices and play a fundamental role in modern electronic and optoelectronic technologies. The importance of sputtering as a viable alternative for obtaining III-Nitride semiconductor compounds is discussed. This is due to its versatility, cost, ease of handling, and advantages provided by the physics of its operation in obtaining thin films compared to techniques such as metal–organic chemical vapor deposition (MOCVD), atomic layer deposition (ALD), and molecular beam epitaxy (MBE). The physics of the sputtering method is briefly and clearly described, including magnetron configurations, plasma generation, energy dependence of sputtering, reactive sputtering, hysteresis effects, target types, and the importance of temperature and working distance between the substrate and target. In addition, the review of the literature on the application of sputtering for obtaining III-Nitride semiconductor compounds is presented. Furthermore, this review also highlights the future of sputtering, which is moving towards high-power pulsation, atomic-level precision, and AI-driven automation due to the miniaturization of electronics, advances in green technology, and innovations in plasma control to increase film density and reduce target material loss. Full article

The Xiaoyinuogaigou (XYN) gold deposit is located in the central Erguna Metallogenic Belt, northeastern China, and represents a characteristic example of Mesozoic gold mineralization in the Mongol–Okhotsk orogenic province. Despite its economic significance, the timing of mineralization and the nature of the ore-forming fluid system have not been well constrained. To address these questions, a systematic investigation of fluid inclusions, isotopes, geochemistry, and geochronology was conducted. The study reveals that: (i) four types of fluid inclusions are identified in auriferous quartz veins, with co-existing aqueous liquid-vapor and NaCl daughter-mineral three-phase inclusions, indicating the involvement of at least two chemically distinct fluids; (ii) the ore-forming fluids are characterized by moderate temperatures (163.2–357.6 °C), low to moderate salinities (3.06–11.34 wt% NaCleqv.), and H–O isotope compositions (δD = −133.3 to −112.3‰; δ¹⁸O fluid (SMOW) = +1.74 to +4.06‰) consistent with a hydrothermal system incorporating a substantial non-magmatic water component; and (iii) REE geochemistry and sulfur isotopes (δ³⁴S = +4.47 to +11.75‰, mean +8.29‰, n = 4) indicate that ore-forming materials were derived at least in part from the ore-hosting granite porphyry. Zircon U–Pb geochronology constrains the granite porphyry crystallization to 180 ± 3 Ma, and hydrothermal monazite U–Pb dating yields an age of 162.3 ± 3.6 Ma (MSWD = 0.95), for a Middle Jurassic hydrothermal event. We therefore conclude that XYN is an epizonal orogenic gold deposit formed during the late compressional to post-collisional transition of the Mongol–Okhotsk orogeny. Full article