This paper examines non-volatile metal oxide semiconductor (MOS) capacitive memory based on WO3/β-Ga2O3 heterostructure nanowire arrays. The WO3/β-Ga2O3 vertical oriented axial heterostructure nanowires (VAHNWs) were synthesized using glancing angle deposition (GLAD) technique installed in an RF sputtering system. The fabricated VAHNWs were also subjected to air annealing at 600 ˚C for 1 hour. The interface trap density (D_it) decreased from 1.7×10^10 〖eV〗^(-1) 〖cm〗^(-2) (as-deposited) to 1×10^10 〖eV〗^(-1) 〖cm〗^(-2)(annealed) which is consistent with a reduction in electrically active interface states. The MOS capacitor exhibited a significant memory window of approximately 5.35 V at ± 8 V and stable endurance over 2000 programming/erasing cycles. Moreover, a charge retention duration as long as 3.5×10^(4 ) s was observed after annealing. These enhanced parameters can be ascribed to the annealing-induced modification of electrically active defects together with improved interface quality. The results demonstrated the thermally annealed WO3/β-Ga2O3 VAHNWs as a promising candidate for future non-volatile memory technologies..
Monodisperse inorganic nanocrystals are pivotal in catalysis, optoelectronics, energy conversion and storage, and biomedicine, yet an ideal synthesis method that simultaneously satisfies room-temperature operation, green chemistry, ultrafast kinetics, low cost, and large-scale feasibility still remains challenging. This review critically benchmarks solution-phase methods for monodisperse inorganic nanocrystals, including hydrothermal/solvothermal synthesis, hot-injection and heat-up routes, two-phase liquid–liquid synthesis, conventional long-chain ligand-assisted coprecipitation, and short-chain ligand-assisted coprecipitation (SCLAC). In this review, we first summarize the principles, advantages, and limitations of conventional methods, then discuss the formation mechanism of monodisperse nanoparticles, with emphasis on the distinction between classical LaMer-type burst nucleation and non-classical or ligand-mediated nucleation/growth pathways. We then evaluate SCLAC as a promising candidate for green and scalable synthesis. SCLAC uses short-chain fatty acid and aliphatic amine ligands in ethanol/water under ambient conditions and has enabled sub-5 nm rare-earth-doped oxide and fluoride nanocrystals with high photoluminescence quantum yields and batch scales up to the kilogram level. However, its greenness, cost, mechanism, and generality across other material classes require further quantitative validation. We conclude by outlining a roadmap for extending SCLAC to metal sulfides, noble metals, multicomponent systems, and continuous-flow manufacturing, while clearly distinguishing experimentally demonstrated advantages from proposed mechanisms and future opportunities.
β-Ga₂O₃ has attracted significant attention as an ultra-wide-bandgap semiconductor for high-power electronics, solar-blind photodetectors, and sensors operating in extreme environments owing to its wide bandgap, high critical electric field, and the commercial availability of melt-grown substrates. Radio frequency (RF) magnetron sputtering is a scalable and economical thin-film deposition technique; however, correlations between sputtering conditions and β-Ga₂O₃ film properties remain less systematically established than those for mature epitaxial methods. This review critically examines RF magnetron-sputtered β-Ga₂O₃ thin films with emphasis on substrate selection, substrate temperature, RF power, oxygen-to-argon ratio, sputtering pressure, and post-deposition annealing. The reviewed literature indicates that high-quality films are most consistently obtained on c-plane sapphire, with conventional in situ growth temperatures of approximately 650-800 °C, moderate RF power near 100-120 W, nominal, system-dependent O₂/Ar ratios commonly around 5-10% and in some systems extending toward ~15%, intermediate sputtering pressures near 6-10 mTorr, and post-deposition annealing at 800-1000 °C when low-temperature growth is used. These ranges should not be interpreted as universal recipes; rather, they define conditional process windows that depend on target geometry, plasma conditions, oxygen activity, pressure-dependent scattering, film thickness, and thermal history. By organizing recent studies into coupled growth regimes, this review provides a process-map framework for improving reproducibility and guiding application-specific β-Ga₂O₃ thin-film deposition by RF magnetron sputtering.
Bacterial infection severely impairs wound repair, and antibiotic-based treatment is increasingly challenged by antimicrobial resistance. Herein, Fe3O4 nanozymes with octahedral, spherical, and cubic morphologies were synthesized and systematically compared for peroxidase-like activity, photothermal performance, and antibacterial efficacy. Despite their comparable sizes and good dispersibility, the three nanozymes exhibited distinct morphology-dependent catalytic activities. Octahedral Fe3O4 nanoparticles (O-IONP) showed the highest POD-like activity, strongest hydroxyl radical generation, lowest apparent Michaelis constant toward TMB, and highest maximum reaction velocity. The catalytic activity of Fe3O4 nanozymes increased with temperature and reached an optimum near 55 oC, indicating the feasibility of photothermalenhanced catalysis. Under 808 nm near-infrared irradiation, O-IONP displayed the most efficient photothermal response and reached a temperature favourable for POD-like catalysis. In vitro, O-IONP combined with NIR reduced Escherichia coli viability to approximately 2% and caused severe bacterial membrane deformation, collapse, and rupture, while maintaining acceptable cytocompatibility toward macrophages. In an E. coli-infected wound model, O-IONP with NIR significantly accelerated wound closure, reducing the wound remaining ratio to approximately 13% on day 10. This work demonstrates a simple morphology-engineered Fe3O4 nanozyme platform for photothermal-catalytic antibacterial therapy and infected wound healing.
Constructing type-II heterojunctions is an effective way to enhance the photoelectrochemical (PEC) performance of semiconductor-based materials. In this study, in order to increase the specific surface area, a novel coral-like 3D porous Ta3N5 nanostructure was first synthesized via a hydrothermal method. Subsequently, CdS quantum dots were deposited on the coral-like Ta3N5 substrate by a successive ionic layer adsorption and reaction method with 40, 80, and 120 cycles (named Ta3N5/CdS-40, Ta3N5/CdS-80, and Ta3N5/CdS-120) to modulate the band structures and optical absorption properties of the composites. The results show that Ta3N5/CdS-80 exhibits a continuous and dense CdS overlayer with effectively passivated surface states, delivering the optimal PEC performance (3625 mu A & centerdot;cm(-2) at +1 V about 39 times that of the pure Ta3N5). This is because the Type-II heterojunction between CdS and Ta3N5 facilitates the separation of photogenerated carriers, and the high-quality CdS coating reduces the capture of photogenerated carriers by defects. When coupled with 304 stainless steel, Ta3N5/CdS-80 yields a photovoltage drop of 0.39 V and a net photocurrent density of 99.39 mu A & centerdot;cm(-2), significantly outperforming the Ta3N5/CdS-40 and Ta3N5/CdS-120 samples. This work provides experimental evidence for the development of superior Ta3N5-based photogenerated cathodic protection materials.
