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The Growth Window of Ferroelectric Epitaxial Hf <sub/>0.5</sub> Zr <sub/>0.5</sub> O <sub/>2</sub> Thin Films
摘要： The metastable orthorhombic phase of hafnia is generally obtained in polycrystalline films, whereas in epitaxial films its formation has been much less investigated. We have grown Hf0.5Zr0.5O2 films by pulsed laser deposition and the growth window (temperature and oxygen pressure during deposition, and film thickness) for epitaxial stabilization of the ferroelectric phase is mapped. The remnant ferroelectric polarization, up to around 24 μC/cm2, depends on the amount of orthorhombic phase and strain, and increases with temperature and pressure for fixed film thickness. Leakage current decreases by increasing thickness and temperature, and particularly by reducing oxygen pressure. The coercive electric field (EC) depends on thickness (t) according the EC - t-2/3 scaling, which is observed by the first time in ferroelectric hafnia, and the scaling extends to thickness below 5 nm. The proven ability to tailor functional properties of high quality epitaxial ferroelectric Hf0.5Zr0.5O2 films paves the way towards progress in understanding their ferroelectric properties and prototyping devices.
关键词： Growth parameters,Pulsed laser deposition,Ferroelectric HfO2,Ferroelectric oxides,Epitaxial stabilization,Oxide thin films
更新于2025-09-23 15:22:29
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Influence of Local Heterojunction on the Thermoelectric Properties of Mo-SnSe Multilayer Films Deposited by Magnetron Sputtering
摘要： Mo-SnSe multilayer films were deposited by multi-step magnetron sputtering. The Mo-SnSe multilayer films are then annealed, and the new phases including SnSe2 and MoSe2 are observed by x-ray diffraction and Raman spectroscopy. Scanning electron microscopy reveals that the SnSe exhibits the columnar grain structure with sizes from 50–100 nm. The high-resolution transmission electron microscopy shows the SnSe2 is dispersed at the boundary of the columnar grain and the local MoSe2/SnSe heterojunction is formed in the interior of the columnar grain. The influence of Mo content on the thermoelectric properties of SnSe thin films was investigated. A maximum power factor of 0.44 μW cm?1 K?2 was obtained for a 2.6 at.% Mo-doped SnSe thin film at 576 K, which is higher than that of a SnSe thin film deposited under the same conditions.
关键词： thermoelectric properties,heterojunction,SnSe films,sputtering
更新于2025-09-23 15:22:29
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AIP Conference Proceedings [AIP Publishing LLC NANOFORUM 2014 - Rome, Italy (22–25 September 2014)] - Structural and optical properties of Sn1-xMnxO2 thin films
摘要： Sn1-xMnxO2 thin films are deposited by spray pyrolysis method. XRD of all the thin films show the amorphous nature. Synthesis of SnO2 is also confirmed by FTIR spectroscopy. Undoped SnO2 thin film is 60-70 % transparent in visible and near IR region and it increases up to80-90% for 20 at. % Mn doped SnO2 thin film. The optical band gap is tunable linearly between 3.34 to 3.96 eV for 0≤x≤0.20 for Sn1-xMnxO2 amorphous thin films.
关键词： and FTIR,Thin Films,Band Gap,Optical Transmission
更新于2025-09-23 15:22:29
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Blue-emitting Photostable Hybrid Films for High-efficiency Large-area Light Converter and Photonic Applications
摘要： A blue fluorophore of Schiff base zinc complex is prepared by a hydrolysis-free solution-based synthetic method. Under UV excitation, the complex produces blue emission with a quantum yield (Q) of 42.6% in methylene chloride and 24.0% in standalone powder form. Quantum mechanical calculations show that the blue emission is generated by the change in the chemical state of the ligand associated with the complexation with Zn cations. Thin films of Zn complexes incorporated in polymethylmethacrylate (PMMA) and cellulose acetate butyrate (CAB) polymers are also prepared by dispersing the complexes into the polymer matrices. These hybrid polymer films exhibit several notable features, particularly enhanced luminescence efficiency (with maximum Q of 85.8% for PMMA and 30.0% for CAB) and scalability for fabrication over a large area while retaining the original properties of the host polymers. Light-emitting diodes are also fabricated using the CAB hybrid thin films, and they show a Q of 43.2% with excellent photostability. The complex and its hybrid films demonstrate their great potential for such applications as UV-to-blue conversion devices in photoelectronics, solar-cell concentrators, solid-state lighting and display, and green-house agriculture.
关键词： blue emission,photostable hybrid films,Schiff base,Fluorescent polymer films
更新于2025-09-23 15:21:21
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Electrical and optical responses of composite films based on N,N-dimethylamino-4′-N′-methylstilbazolium 2,4,6-trimethylbenzenesulfonate (DSTMS)-graphene
摘要： N,N-dimethylamino-4′-N′-methylstilbazolium 2,4,6-trimethylbenzenesulfonate (DSTMS)-graphene ex-situ and in-situ composite films with 2% concentration of graphene were first prepared and systematically investigated. The crystallinity of DSTMS-based composite films were confirmed by XRD analysis, and the functional groups of composite films can be obtained by FT-IR. Optical absorptions were recorded using UV–Vis-NIR spectral analysis, and the band gap and extinction coefficient of the films were calculated. The thermal stability of the composite films were analyzed by TG/DSC. The pressure sensitive resistance test showed that the pressure sensitive signal of the composite films were significantly increased after graphene added, while the signal of DSTMS film eventually disappears. This work expands the application of organic nonlinear crystal DSTMS in optics and electricity by doping graphene.
关键词： DSTMS,electrical properties,graphene,composite films,optical properties
更新于2025-09-23 15:21:21
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Effect of Ag incorporation on structural and opto-electric properties of pyrolized CdO thin films
摘要： We have investigated the structure, morphology and opto-electric properties of CdO and Ag-incorporated CdO thin films prepared by chemical spray pyrolysis (CSP) method. The X-ray diffraction (GIXRD) study confirms that CdO samples are highly polycrystalline with cubic structure. The AFM study shows smooth surfaces both for CdO and Ag-CdO thin films. The direct band gap energy varies from 2.25 to 2.50 eV depending on Ag content in the films. Urbach energy reversal in optical band gap indicates that several localized states are present above Fermi level or near at the conduction band. The optical properties, such as refractive index, optical conductivity and nonlinear optical susceptibility, are found dependent on Ag content. A combined effect on the transport properties has been observed with the incorporation of Ag in CdO. The metal-like electric conduction of CdO film has been removed up to a temperature Tc for Ag doping. The n-type carrier concentration of CdO is reduced with increasing Ag content and the concentration is of the order of ~ 1020 cm?3.
关键词： Band gap,Activation energy,Thin films,XRD,Urbach tail
更新于2025-09-23 15:21:21
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Electrochemical properties of chemically synthesized SnO2-RuO2 mixed films
摘要： The SnO2–RuO2 mixed films are prepared by successive ionic layer adsorption and reaction (SILAR) method. The SnO2 films combined with RuO2 are prepared by varying the deposition cycles of SILAR. The effect of combining SnO2 with RuO2 on structural, morphological and electrochemical properties is studied. It is observed that the crystalline nature of SnO2 changed to amorphous with increase in RuO2 deposition cycles. The morphology is also changed from fibrous-porous to compact after increasing RuO2 deposition cycles. The specific capacitance of SnO2 is increased from 4 to 185 F/g after combined with RuO2. The maximum utilization of RuO2 is observed with specific capacitance of 1010 F/g.
关键词： RuO2,SnO2,Supercapacitor,Thin films,Chemical synthesis,Charge–discharge
更新于2025-09-23 15:21:21
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Photothermal-Assisted Optical Stretching of Gold Nanoparticles
摘要： The synergy of photothermal energy and optical forces generated by tightly focused laser beams can be used to transform the shape of gold nanoparticles. Here, the combination of these two effects is demonstrated to be an effective way of elongating gold nanoparticles (Au NPs), massively tuning their plasmonic properties. The photothermal effect of the laser increases the temperature of Au NPs above the melting point, and optical forces deform the molten Au NPs. As a result, the shape of Au NPs transforms from nanospheres into nanorods or dimers, depending on the power and time of irradiation as well as the surface energy of the substrate. This process is reversible by using high laser power to transform nanorods back to nanospheres due to capillary dewetting. Such light-induced transformations of nanostructures not only provide a facile way to tune plasmon resonances but also shed light on how the synergistic effect of photothermal energy and optical forces works on plasmonic nanoparticles.
关键词： rods,films,dimers,optical forces,plasmons
更新于2025-09-23 15:21:21
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Humidity sensing characteristics of Sb2O3 thin films with transitional electrical behavior
摘要： The quest for smaller and more efficient humidity sensors is still on. Antimony trioxide thin films deposited by vacuum thermal evaporation onto heated glass substrates are analyzed as water vapor sensors, along with the study of their morpho-structural and electrical properties. Several substrate temperatures were set during the depositions, leading to films with significantly different electrical and humidity sensing features. Unusual increase of the electrical resistance of the films with temperature above 170 ?C was noticed, representing the intermediate stage between extrinsic and intrinsic conductivity. In the extrinsic conduction region, the activation energy decreases exponentially with the substrate temperature during the initial depositions. The alternative current (AC), i.e. the electrical frequency characteristics versus humidity were also studied, allowing for the identification of the conduction mechanism within the samples, which is most probably short range hopping of charge carriers through trap sites, influences by the changing grain size and remanent amorphous phase within the films.
关键词： Activation energy,Humidity sensitivity,Antimony trioxide,Thin films,Frequency characteristics
更新于2025-09-23 15:21:21
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Self-structuring in Zr1?xAlxN films as a function of composition and growth temperature
摘要： Nanostructure formation via surface-diffusion-mediated segregation of ZrN and AlN in Zr1?xAlxN films during high mobility growth conditions is investigated for 0 ≤ × ≤ 1. The large immiscibility combined with interfacial surface and strain energy balance resulted in a hard nanolabyrinthine lamellar structure with well-defined (semi) coherent c-ZrN and w-AlN domains of sub-nm to ~4 nm in 0.2 ≤ × ≤ 0.4 films, as controlled by atom mobility. For high AlN contents (x > 0.49) Al-rich ZrN domains attain wurtzite structure within fine equiaxed nanocomposite wurtzite lattice. Slow diffusion in wurtzite films points towards crystal structure dependent driving force for decomposition. The findings of unlikelihood of iso-structural decomposition in c-Zr1?xAlxN, and stability of w-Zr1?xAlxN (in large × films) is complemented with first principles calculations.
关键词： phase separation,nanostructure,thin films,self-organization,ZrAlN
更新于2025-09-23 15:21:21