This study systematically investigates the synergistic effects of thermal annealing (400–600 °C) and indium (In) doping (3 at.%) on sol–gel dip-coated zinc oxide (ZnO) thin films. Structural, morphological, and optical properties were characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy, UV–Vis spectroscopy, photoluminescence (PL), and Fourier transform infrared spectroscopy (FTIR). XRD confirmed the wurtzite structure in films annealed at 500 °C, with In doping inducing preferential (100) orientation. SEM revealed annealing-dependent grain growth in pure ZnO, while In doping suppressed coalescence, reduced roughness, and promoted nanotube formation above 500 °C. UV–Vis analysis showed 84% UV transmittance for pure ZnO annealed at 400 °C due to an antireflective nanoamorphous microstructure, while 3 at.% In doping combined with 600 °C annealing enhanced visible transmission beyond 95% through controlled suppression of oxygen vacancies. Complementary optical analyses demonstrated bandgap widening from 3.57 to 3.80 eV (Burstein–Moss effect), and PL spectra confirmed In 3+ -mediated oxygen vacancy passivation (reduced green/red emissions) with enhanced near-band-edge luminescence at 500 °C. FTIR analysis confirmed that In neutralizes electronegative impurities, passivates O–H defects (3354 cm −1 ), and strengthens Zn–O bonds (450–500 cm −1 ). Optimal properties, including high crystallinity, >95% visible transmittance, and a widened bandgap, were achieved for 3 at.% In-doped ZnO annealed at 500 °C. Preliminary antibacterial assessments against Staphylococcus aureus , Bacillus spizizenii , Pseudomonas aeruginosa , and Escherichia coli indicate promising avenues for further study. The work establishes In doping as a critical strategy for enhancing ZnO’s optoelectronic functionality through defect control and textural engineering.
To address the lack of a unified theoretical framework linking single-doping effects with the combined behavior of co-doping in ZnO, this work employs density functional theory (DFT) with a 3 × 3 × 2 ZnO supercell (Zn 36 O 36 ) to construct and compare Na-, Mg-, and Al-doped configurations, including single-doped (NaZn 35 O 36 , MgZn 35 O 36 , AlZn 35 O 36 ), binary co-doped (NaMgZn 34 O 36 ,NaAlZn 34 O 36 , MgAlZn 34 O 36 ), and ternary co-doped (NaMgAlZn 33 O 36 ) models. The geometric, electronic, and optical properties are analyzed within a consistent computational framework based on GGA-PBE, with additional PBE+U calculations ( U = 8 eV applied to Zn-3d states) performed to further examine the reliability of the band-structure trends. The calculations show that single doping establishes the basic trends of band-edge modulation and donor-/acceptor-like behavior, binary co-doping introduces dopant–dopant introduces dopant–dopant interactions that modify the optical response but may also induce localized features and spectral non-uniformity in certain cases. The ternary NaMgAlZn 33 O 36 configuration exhibits a comparatively balanced electronic structure with smoother dielectric evolution, enhanced absorption characteristics, and a relatively stable energy-loss peak, consistent with a reduced influence of localized perturbations. Overall, these results provide insight into the combined influence of multi-element co-doping on the electronic and optical response of ZnO and provide a comparative theoretical reference for designing ZnO-based optoelectronic materials with tunable band edges and high transparency.
In this work, copper oxide thin films are deposited on glass and silicon substrates by tilt chemical spray pyrolysis (CSP). Then, the films are electrochemically etched by ammonia for different etching times and currents. The effect of etching is studied with respect to structural, optical, and electrical properties of CuO thin films. XRD examination exhibited distinct diffraction peaks corresponding to the monoclinic phase at 2 θ ≈ 32.5°, 35.5°, and 38.7°. FESEM analysis revealed spherical nanostructures for etched CuO films. AFM analysis confirmed that the surface of etched CuO was uniform with a higher particle size and modified surface roughness. The optical bandgap energy values of the etched CuO thin films were in the range between 2.14 and 2.25 eV. The CuO films deposited on n-type Si and p-type are used as CuO/nSi and CuO/pSi heterojunction photodetectors in the visible and near-IR regions. The results demonstrated that electrochemically textured CuO/Si photodetectors for certain texturing conditions exhibited superior performance compared to their untextured counterparts, offering enhanced absorption coefficients, improved spectral responsivity, and reduced dark current.
A central challenge in spintronics is the development of materials for efficient spin-polarized current generation. While crystalline Heusler alloys often fall short of predicted half-metallicity due to structural disorder, their amorphous analogs present a promising avenue. In this work, we investigate how the composition-dependent structural evolution of short-range order controls room temperature electronic transport in amorphous FexSi1−x (0.44 ≤ x ≤ 0.75) alloy thin films. This structural evolution, revealed by X-ray reflectivity, underpins a transition from hopping to metallic conduction across distinct amorphous phases (FeSi → Fe2Si → Fe3Si). In the FeSi-like phase region, electronic transport is governed by Mott variable-range hopping, resulting in high resistivity and low Hall mobility. The onset of metallic conduction within the amorphous Fe2Si- and Fe3Si-like composition ranges yields lower resistivity alongside enhanced hole mobility. Our results establish a direct structure-property relationship in amorphous FexSi1−x alloys, demonstrating the ability to selectively design electronic transport through fine compositional tuning. Understanding the interplay between local atomic order and electronic transport in amorphous Fe–Si alloys provides key insights for engineering next-generation spintronic devices.
Nickel-based superalloys are widely deployed in high-pressure compressors and turbine rotors in various aeroengines. Developing advanced processing strategies is essential to boost the service performance of the alloy. In this work, molecular dynamics simulations based on the modified analytical embedded-atom method are performed to investigate the uniaxial tensile behaviors of γ/γ′ nanowires (NWs). The cross-sectional sizes of NWs range from 1.416 to 4.249 nm, and the simulation temperatures vary from 100 to 700 K. Cross-sectional size and temperature serve as key factors for surface activity, which in turn exerts a significant influence on the mechanical properties. The results obtained demonstrate that the mechanical properties increase exponentially with increasing cross-sectional size but decrease linearly with the rising temperature. Surface activity, including surface energy and surface thickness, acts as the driving force for dislocation or slip nucleation and is regulated by size and temperature. The critical size threshold for the transition of deformation mechanisms from crystal slip to twin formation is approximately 2.75 nm, as the size and temperature have a synergistic effect on the surface energy. The coupled effect of size, temperature, and surface, each of which imposes distinct regulatory roles, respectively, collectively governs the deformation behavior and mechanisms of NWs. In small NWs, deformation is primarily dominated by dislocation glide. By contrast, in larger NWs, plastic deformation is dominated by twin-mediated plasticity that impedes the dislocation movement and lattice glide. The study reveals the coupled size–temperature–surface effects on the deformation behaviors, which provides a theoretical foundation for the design of superalloys used in extreme environments.
