Search Results (202)

In this work, Ba_0.6Sr_0.4TiO₃ (BST) films were deposited on Si(100) and Pt(111)/Ti/SiO₂/Si(100) substrates using the pulsed laser deposition (PLD) technique. The effects of TiO₂ buffer layer thickness and preparation temperature on the microstructure and electrical properties of BST films were studied in detail. We intensively investigated the influence of the TiO₂ buffer layer on the microstructure of BST films by using X-ray diffraction and scanning electron microscopy. We found that anatase crystalline TiO₂ buffer layers within 15 nm thicknesses could significantly change the BST films from an irregular orientation to the (111) preferential orientation. The TiO₂ anatase layers could promote the growth of BST film grains for obtaining minimal stress and low lattice distortion, increase the nucleation density, and improve its surface morphology, resulting in higher dielectric constant and resistance voltage, and lower dielectric loss and leakage current density. The dielectric constant, dielectric loss, and dielectric tunability of the BST devices with 8 nm thick TiO₂ anatase buffer layers at 1 MHz were 856.5, 0.017, and 64.3%, respectively. The achieved high dielectric tunability indicates BST with TiO₂ anatase buffer layers as one of the encouraging candidates for RF and microwave tunable applications at room temperature. Full article

A three-dimensional Ag/TiO₂/Ti foam was fabricated via thermal annealing followed by pulsed laser deposition (PLD), providing a simple and scalable fabrication strategy. The porous Ti foam framework allows for the uniform dispersion of Ag nanoparticles (NPs), while the thermally formed TiO₂ interlayer promotes synergistic electromagnetic and chemical enhancement mechanisms. The localized electromagnetic field amplification at Ag-TiO₂ interfaces was simulated using the finite-difference time-domain (FDTD) method. Density functional theory (DFT) calculations confirmed that TiO₂ enhances both rhodamine 6G (R6G) adsorption on the substrate and charge transfer (CT) between the substrate and R6G, increasing the SERS activity. The optimized substrate demonstrates exceptional surface-enhanced Raman scattering (SERS) performance with an enhancement factor of 1.9 × 10⁷ and a detection limit of 2.24 × 10⁻¹¹ M for rhodamine 6G, with good reproducibility (RSD = 8.4%). Practical applicability is validated through sensitive detection of food colorants (brilliant blue and allura red). The synergistic combination of CT and electromagnetic enhancement in the easily fabricated Ag/TiO₂/Ti foam enables its application as a promising platform for food safety monitoring, effectively bridging laboratory innovation and practical applications. Full article

Zinc oxide (ZnO) nanostructures have been intensively investigated for applications in sensing, photocatalysis, and optoelectronic devices, where functional performance is strongly governed by morphology, crystallinity, and defect structure. Conventional wet-chemical and vapor-phase growth methods often require long processing times or complex chemistries and face reproducibility and compatibility challenges when applied to thin, flexible, or curved metallic substrates. Pulsed high-energy techniques—such as pulsed laser deposition (PLD), high-power impulse magnetron sputtering (HiPIMS), and pulsed laser or plasma processing—offer a versatile alternative, enabling rapid and localized synthesis both from and on Zn-bearing thin shells. These methods create transient nonequilibrium conditions that accelerate oxidation and promote spatially controlled nanostructure formation. This review highlights the emerging integration of artificial intelligence (AI) with pulsed ZnO synthesis on thin metallic substrates, emphasizing standardized data reporting, Bayesian optimization and active learning for efficient parameter exploration, physics-informed and graph-based neural networks for predictive modeling, and reinforcement learning for adaptive process control. By connecting synthesis dynamics with data-driven modeling, the review outlines a path toward predictive and autonomous control of ZnO nanostructure formation. Future perspectives include autonomous experimental workflows, machine-vision-assisted diagnostics, and the extension of AI-guided pulsed synthesis strategies to other functional metal oxide systems. Full article

Epitaxial thick films of yttrium iron garnet (YIG) are ideal for use in microwave devices due to their low losses at high frequencies. This report is on the growth of strain-engineered YIG films by liquid-phase epitaxy (LPE) on yttrium aluminum garnet (YAG) substrates with −3% lattice mismatch with YIG. Since the use of a lattice-matched substrate is preferred for LPE growths, a seed layer of YIG, 370–400 nm in thickness, was deposited by pulsed laser deposition (PLD) on (100), (110), and (111) YAG substrates. The seed layers were stoichiometric with magnetic parameters in agreement with the parameters for bulk single-crystal YIG and with strain-induced perpendicular magnetic anisotropy field H_a = 0.19–0.43 kOe. YIG films, 4 to 8.4 μm in thickness, were grown by LPE at 870 °C on YAG substrates with the seed layers using the PbO+B₂O₃ flux and annealed in air at 1000 °C. The films were Y-rich and Fe-deficient and confirmed to be epitaxial single crystals by X-ray diffraction. The saturation magnetization 4πM_s at room temperature was rather high and ranged from 1.9 kG to 2.3 kG. Ferromagnetic resonance at 5–15 GHz showed the absence of significant magneto-crystalline anisotropy in the LPE films with the line-width ΔH in the range 85–160 Oe, and H_a = 0.27–0.80 kOe which is much higher than for the seed layers. The high magnetization and H_a-values for the LPE films could be partially attributed to the off-stoichiometry. Although the strain due to the film–substrate lattice mismatch contributes to H_a, the mismatch in the thermal expansion coefficients for YIG and YAG is also a likely cause of H_a due to the high growth and annealing temperatures. The LPE-grown YIG films with high strain-induced anisotropy fields have the potential for use in self-biased microwave devices. Full article

Rare-earth barium copper oxide (REBCO) high-temperature superconductors, owing to their ability to maintain high critical current density (J_c) under liquid-nitrogen-temperature and high-magnetic-field conditions, are widely regarded as one of the most promising material systems among all superconductors. This review systematically summarizes fabrication strategies for REBCO coated conductors, with a focus on pulsed laser deposition (PLD) for achieving high-quality epitaxial growth with precise composition control. To enhance in-field performance, strategies for introducing artificial pinning centers (APCs) are examined, including rare-earth element doping, substrate surface decoration, and nanoscale secondary phase incorporation. The mechanisms of vortex pinning from different dimensional defects and their synergistic effects are compared. Finally, we suggest potential future directions aimed at further enhancing the superconducting properties. Full article

Zirconium (Zr) thin films were deposited on silicon (Si) substrates via pulsed laser deposition (PLD) using a 248 nm excimer laser. The effects of substrate temperature on film morphology and crystallinity were systematically investigated. X-ray diffraction (XRD) revealed that the Zr(100) plane exhibited the strongest orientation at 400 °C while Zr (002) was maximum at 500 °C. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) analyses demonstrated an increase in surface roughness with temperature, with the smoothest surface observed at lower temperatures and significant island formation at 500 °C due to the transition to 3D growth. At 500 °C, interdiffusion effects led to the formation of zirconium silicide at the Zr/Si interface. To further interpret the experimental findings, computational modeling was employed to analyze the transition from 2D layer-by-layer growth to 3D island formation at elevated temperatures. Using a multi-parameter kinetics-free model based on free energy minimization, the critical film thickness for this transition was determined to be ~1–2 nm, aligning well with experimental observations. A separate kinetic model of island nucleation and growth predicts that this shift is driven by the kinetics of adatom surface diffusion. Additionally, the kinetic simulations revealed that, at 400 °C, adatom diffusivity optimally balances crystallization and surface energy minimization, yielding the highest film quality. At 500 °C, the rapid increase in diffusivity leads to the proliferation of 3D islands, consistent with the roughness trends observed in SEM and AFM data. These findings underscore the critical role of deposition parameters in tailoring Zr thin films for applications in advanced coatings and electronic devices. Full article

This study examines the effects of laser pulse duration on the structural, morphological, optical, and gas-sensing characteristics of ${\mathrm{Al}}_2{\mathrm{O}}_3$/AgO thin films deposited on glass substrates using pulsed laser deposition (PLD). Pulse durations of 10, 8, and 6 nanoseconds were achieved through optical lens modifications to control both energy density and laser spot size. X-ray diffraction (XRD) and atomic force microscopy (AFM) analyses showed a distinct reduction in both crystallite and grain sizes with decreasing pulse width, along with significant improvements in surface morphology refinement and film compactness. Hall effect measurements revealed a transition from n-type to p-type conductivity with decreasing pulse width, demonstrating increased hole concentration and reduced carrier mobility attributed to grain boundary scattering. Furthermore, current-voltage (I-V) characteristics demonstrated improved photoconductivity under illumination, with the most pronounced enhancement observed in samples prepared using longer pulse durations. Gas sensing measurements for ${\mathrm{NO}}_2$ and ${\mathrm{H}}_2$S revealed enhanced sensitivity, improved response/recovery characteristics at 250 °C, with optimal performance achieved in films deposited using shorter pulse durations. This improvement is attributed to their larger surface area and higher density of active adsorption sites. Our results demonstrate a clear relationship between laser pulse parameters and the functional properties of ${\mathrm{Al}}_2{\mathrm{O}}_3$/AgO films, providing valuable insights for optimizing deposition processes to develop advanced gas sensors. Full article

This work explores the relationship between the thickness and the structural, morphological, and optical features of thermally annealed (GaIn)₂O₃ thin films grown by pulsed laser deposition at room temperature. The thickness of the (GaIn)₂O₃ films varied from 20 to 391 nm with an increase in deposition time. The film with a thickness of about 105 nm showed largest grain size as well as the strongest XRD peak intensity, as measured by atomic force microscopy and X-ray diffraction. The studies on the optical properties show that the bandgap value decreased from 5.14 to 4.55 eV with the change in the film thickness from 20 to 391 nm. The film thickness had a significant impact on the structure, morphology, and optical properties of (GaIn)₂O₃, and the PLD growth mode notably influenced the film quality. The results suggest that optimizing the film thickness is essential for improving the film quality and achieving the target bandgap. Full article

In this work, we investigated how the electrical resistivity of LaNiO₃ thin films deposited on SrLaAlO₄ (100), LaAlO₃ (100), and MgO (100) single-crystal substrates by the pulsed laser deposition (PLD) technique can be controlled by femtosecond laser irradiation. Thin films were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (SEM-EDS), and temperature-dependent electrical resistivity measurements. The XRD data indicated good crystallinity and preferential crystallographic orientation. The electronic transport parameters of irradiated samples showed a remarkable decrease in the electrical resistivity for all studied films, which ranged from 38% to 52% depending on the temperature region considered and the type of substrate used. The results indicate a new and innovative route to decrease the electrical resistivity values in a precise, controlled, and localized manner, which could not be performed directly by well-known growth processes, allowing for direct application in non-volatile-memory electrodes. Full article

This review summarizes the recent advances in the application of nanomaterial coatings in optical fiber sensors, with a particular focus on deposition techniques and the research progress over the past five years in humidity sensing, gas detection, and biosensing. Benefiting from the high specific surface area, abundant surface active sites, and quantum confinement effects of nanomaterials, advanced thin-film fabrication techniques—including spin coating, dip coating, self-assembly, physical/chemical vapor deposition, atomic layer deposition (ALD), electrochemical deposition (ECD), electron beam evaporation (E-beam evaporation), pulsed laser deposition (PLD) and electrospinning, and other techniques—have been widely employed in the construction of functional layers for optical fiber sensors, significantly enhancing their sensitivity, response speed, and environmental stability. Studies have demonstrated that nanocoatings can achieve high-sensitivity detection of targets such as humidity, volatile organic compounds (VOCs), and biomarkers by enhancing evanescent field coupling and enabling optical effects such as surface plasmon resonance (SPR), localized surface plasmon resonance (LSPR), and lossy mode resonance (LMR). This paper first analyzes the principles and optimization strategies of nanocoating fabrication techniques, then explores the mechanisms by which nanomaterials enhance sensor performance across various application domains, and finally presents future research directions in material performance optimization, cost control, and the development of novel nanocomposites. These insights provide a theoretical foundation for the functional design and practical implementation of nanomaterial-based optical fiber sensors. Full article

In this study, highly ordered titanium dioxide nanotubes (TiO₂-NTs) have been synthesized using the electrochemical anodization procedure. Subsequently, the TiO₂-NTs were successfully decorated with PbS nanoparticles (NPs) using the pulsed KrF-laser deposition (PLD) technique under vacuum and under different Helium background pressures (P_He) ranging from 50 to 400 mTorr. The prepared samples (PbS-NPs/TiO₂-NTs) were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), and UV–Vis and photoluminescence spectroscopies. XRD analyses confirmed that all TiO₂-NTs crystallized in the anatase phase, while the PbS-NPs crystallized in the cfc lattice. The average crystallite size of the (200) crystallites was found to increase from 21 to 33 nm when the pressure of helium (PHe) was raised from vacuum to 200 mTorr and then dropped back to ~22 nm at P_He = 400 mTorr. Interestingly, the photoluminescence intensity of the PbS-NPs/TiO₂-NTs samples was found to start diminishing for P_He ≥ 200 mTorr, indicating a lesser recombination rate of the photogenerated carriers, which also corresponded to a better photocatalytic degradation of the Amido Black (AB) dye. Indeed, the PbS-NPs/TiO₂-NTs samples processed at P_He = 200 and 300 mTorr were found to exhibit the highest photocatalytic degradation efficiency towards AB with a kinetic constant 130% higher than that of bare TiO₂-NTs. The PbS-NPs/TiO₂-NTs photocatalyst samples processed under P_He = 200 or 300 mTorr were shown to remove 98% of AB within 180 min under UV light illumination. Full article

Lithium niobate (LiNbO₃, LN) is a multifunctional material with broad applicability in photonic and electronic devices. Recent advances in lithium niobate on insulator (LNOI) technology have significantly enhanced the integration density and miniaturization potential of LN-based platforms. Among the various fabrication techniques available, pulsed laser deposition (PLD) presents a cost-effective and versatile alternative to crystalline ion slicing (CIS), particularly advantageous for achieving high doping concentrations. However, a persistent challenge in PLD-grown lithium niobate film is cracking, primarily induced by the substantial thermal stress resulting from the mismatch in thermal expansion coefficients between LN and the substrate. In this study, we implemented a series of process modifications to address the cracking issue and successfully achieved crack-free LN films by introducing a lithium-deficient phase. This approach enabled the successful fabrication of highly Fe³⁺-doped LN films with a high electrical conductivity of 9.95 × 10⁻⁵ S/m while also exhibiting characteristic polarization switching behavior. These results demonstrate that PLD enables the fabrication of highly doped, structurally robust LN films and holds significant potential for the development of advanced electronic and optoelectronic devices. Full article

Transparent conductive oxides (TCOs) have become essential components in a broad range of modern devices, including smartphones, flat-panel displays, and photovoltaic cells. Currently, indium tin oxide (ITO) is used in approximately 90% of these devices. However, ITO prices continue to rise due to the limited supply of indium (In), making the development of alternative materials for TCOs indispensable. Therefore, this study highlights the latest advances in creating new, affordable materials, with a focus on aluminum-doped zinc oxide (AZO). Over the last few decades, this material has been widely studied to improve its physical properties, particularly its low electrical resistivity, which can affect the performance of various devices. Now, it is close to replacing ITO due to several advantages including cost-effectiveness, stability under hydrogen plasma, low processing temperatures, and lack of toxicity. Besides that, in comparison to other TCOs such as IZO, IGZO, or IZrO, AZO achieved a low electrical resistivity (10⁻⁵ ohm cm) while maintaining a high transparency across the visible spectrum (over 85%). Additionally, due to the increasing development of technologies utilizing such materials, it is essential to develop more effective techniques for producing TCOs on a larger scale. Additionally, due to the increasing development of technologies utilizing such materials, it is essential to develop more effective techniques for producing TCOs on a larger scale. This review emphasizes the potential of AZO as a cost-effective and scalable alternative to ITO, highlighting key advancements in deposition techniques such as pulsed laser deposition (PLD). Full article

Two-dimensional film materials with unique atomic structures and electronic operation modes have demonstrated amazing application potential and value in the field of high technology. Among the various methods for preparing 2D film materials, PLD technology has become the preferred technology for rapid and green preparation of high-quality, complex structured 2D film materials due to its features such as maintaining the excellent stoichiometric ratio of the target, strong process flexibility, and non-polluting environment. Therefore, this paper discusses the exciting topic of PLD technology in the preparation and application of 2D film materials. Based on a systematic exposition of its basic principles and influencing factors, it provides a detailed overview of the current application status of PLD technology in the preparation of various 2D film materials such as carbides, sulfides, oxides, nitrides, and perovskites. Meanwhile, the advantages and disadvantages of PLD technology in the preparation of 2D film materials were also positively summarized, and the challenges and emerging strategies it faces in the future preparation of 2D film materials were cautiously discussed. This provides practical suggestions and reflections for the sustainable development of PLD technology in the fields of basic research, performance regulation, device development, and application of 2D film materials preparation. Full article

Ferroelectric thin films with a high dielectric tunability (η) have great potential in electrically tunable applications, including microwave tunable devices such as phase shifters, filters, delay lines, etc. Using a modified Landau–Devonshire type thermodynamic potential, we show that the dielectric tunability η of a (001) tetragonal ferroelectric film can be analytically solved. After a survey of materials, a large η value above 60% was predicted to be achievable in a (001)-oriented tetragonal Pb(Zr_0.52Ti_0.48)O₃ (PZT) film. Experimentally, (001)-oriented PZT thin films were prepared on LaNiO₃-coated (100) SrTiO₃ substrates by using pulsed laser deposition (PLD). These films exhibited good dielectric tunability (η ~ 67.6%) measured at a small electric field E of ~250 kV/cm (corresponding to 5 volts for a 200 nm thick film). It only dropped down to ~54.2% when E was further reduced to 125 kV/cm (2.5 volts for 200 nm film). The measured dielectric tunability η as functions of the applied electric field E and measuring frequency f are discussed for a 500 nm thick PZT film, with the former well described by the theoretical η(E) curves and the latter showing a weak frequency dependence. These observations validate our integrated approach rooted in a theoretical understanding. Full article