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[IEEE 2018 20th International Conference on Transparent Optical Networks (ICTON) - Bucharest (2018.7.1-2018.7.5)] 2018 20th International Conference on Transparent Optical Networks (ICTON) - Third Harmonic Generation of Azo-Based Thin Films
摘要： This paper presents investigation results of the linear and nonlinear optical properties for thin films containing azo-based compounds. Thin films were deposited on a glass substrate using spin coating technique. The linear optical properties were examined by using Absorption method. The nonlinear optical properties as well as Third Harmonic Generation were examined by means of Maker fringe technique by exploiting Nd:YAG laser at a wavelength 1064 nm. Third-order nonlinear optical susceptibility were calculated using theoretical model.
关键词： third harmonic generation,azo-based compounds,nonlinear optical response,thin film,nonlinear susceptibility
更新于2025-09-10 09:29:36
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Ternary Ti–Si–C alloy film formation on GaN and contact properties
摘要： Ternary Ti–Si–C alloy films were deposited on GaN substrates (n-type and p-type) by the radio- frequency magnetron sputtering method. The electrical properties of contact films with various chemical compositions were investigated. The microstructures were examined by X-ray diffractometry and transmission electron microscopy. The electrical properties of the contact films were improved after annealing at 873 K for 60 s. Ohmic contact characteristics were obtained for n-type GaN. The TiN phase plays an important role in obtaining the ohmic contact. The effect of deposition and annealing on the electrical properties between Ti–Si–C film and GaN are discussed based on the experimental results.
关键词： Compound semiconductors,Contact properties,GaN,Ohmic contact,Thin film
更新于2025-09-10 09:29:36
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Effect of precursor dopant valence state on the photocatalytic performance of Mo3+- or Mo5+-Doped TiO2 thin films
摘要： Mo3+- or Mo5+-doped TiO2 sol-gel thin films (≤0.100 mol%) were spin coated on fused silica glass substrates and annealed at 450°C for 2 h. The effect of the valence of the dopant precursor is significant to the nanostructural development and resultant properties. Mo3+ or Mo5+ doping yields converse trends with doping level, thus reflecting the competing influences of lattice distortion and destabilization (dominating Mo3+ doping) and nucleation and recrystallization (dominating Mo5+ doping). Mo doping results in oxidation of Mo3+ and reduction of Mo5+, both of which alter to Mo(5-x)+, as well as oxidation of Ti3+ to Ti(4+x)+; all of these result in (cid:1)(cid:2) annihilation. Although the absorption edges were largely indistinguishable Mo3+ doping causes a red shift and Mo5+ doping causes a blue shift. These data suggest that the performances are controlled by the synergistic effects of crystallinity, surface area, and band gap, with the latter’s exhibiting the dominant effect. This suggests that the defect structure governs the photocatalytic performance but also that the defect chemistry at these low annealing temperatures is indicative of nonequilibrium conditions, thereby explaining the significance of the dopant valence.
关键词： Photocatalysis,Dopant Valence,Anatase,Thin Film,Titania
更新于2025-09-10 09:29:36
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Copper Chalcopyrites for Solar Energy Applications
摘要： Solar photovoltaic (PV) technology is a reliable and environmental friendly alternative for electricity generation. There are a number of solar PV technologies at different maturity levels, ranging from well-established and commercialized silicon PV to still in conceptual and R&D phase quantum dot and organic/polymer solar cells. Chalcopyrite solar cells, named so because of the thin absorber layer of Cu-based chalcopyrite materials used in these cells, are one of the frontrunners in thin-film PV technology owing to their tunable direct bandgap, large absorption coefficient and long-term stability. Among all Cu-chalcopyrite materials, copper indium selenide (CISe) and copper indium gallium selenide (CIGSe) are most suitable for use as light-absorbing layer. Although CISe and CIGSe absorber-based PV modules are being produced commercially for several years now, the technology is yet to mature fully as there is still scope for improvement in efficiency, manufacturability and cost reduction. The present article discusses the status of CISe-/CIGSe-based thin-film PV technology while primarily focusing on the absorber material. Different vacuum and non-vacuum methods for fabricating these materials are reviewed along with their merits/demerits and suitability to large-scale production. Current status of commercial maturity for CIGSe PV is discussed while providing general process details of selected industrial manufacturers. Existing bottlenecks for this technology are deliberated, and future directions for improvement in laboratory-scale efficiency and manufacturability are outlined.
关键词： Thin-film solar cells,Chalcopyrite,Copper indium gallium selenide,Copper indium selenide
更新于2025-09-10 09:29:36
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Photocurrent Characteristics of Zinc-Oxide Films Prepared by Using Sputtering and Spin-Coating Methods
摘要： The photocurrent characteristics of zinc-oxide (ZnO) thin-film transistors (TFTs) prepared using radio-frequency sputtering and spin-coating methods were investigated. Various characterization methods were used to compare the physical and the chemical properties of the sputtered and the spin-coated ZnO films. X-ray photoelectron spectroscopy was used to investigate the chemical composition and state of the ZnO films. The transmittance and the optical band gap were measured by using UV-vis spectrometry. The crystal structures of the prepared ZnO films were examined by using an X-ray diffractometer, and the surfaces of the films were investigated by using scanning electron microscopy. ZnO TFTs were prepared using both sputter and solution processes, both of which showed photocurrent characteristics when illuminated by light. The sputtered ZnO TFTs had a photoresponsivity of 3.08 mA/W under illumination with 405-nm light while the solution-processed ZnO TFTs had a photoresponsivity of 5.56 mA/W. This study provides useful information for the development of optoelectronics based on ZnO.
关键词： Phototransistor,Sputter,Thin film transistor,Solution process,Zinc Oxide
更新于2025-09-10 09:29:36
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The Surface and Interface Engineering Multi-Layered Nanopore Films for Enhanced Fabry-Pérot Interferences
摘要： In this study, a broadly-tunable nanoporous thin film system with alternating layers of Ag/indium tin oxide (ITO)/CoFeB/ITO/Ag, which was fabricated on a porous anodic aluminum oxide (AAO) substrate, was presented, so as to achieve the flexible tailoring of the Fabry-Pérot interference. The experimental results demonstrated that the amplitude of the Fabry-Pérot interference of this system, which had only an Ag layer deposited on the AAO substrate, was 12 times higher than that of pure AAO film, aside from the tunable oscillation periods. This was mainly due to the fact that the Ag mirror greatly improved the reflectivity of the air/AAO interface, rendering the intensities of light reflected from the air/AAO and AAO/Al interfaces comparable, thereby forming an effective interference enhancement. Furthermore, the existence of the ferromagnetic CoFeB layer was capable of significantly improving the absorbance in the ultraviolet and visible spectral ranges, and, in particularly, the oscillation ranges could be extended to the near-infrared spectral range (> 2,600 nm) by utilizing an ITO with lower conductivity as a spacer layer, due to its material dispersion which was approximately equal to zero. This new nanoporous thin film system represents a powerful tool for the future development of ultrasensitive optical devices based on the Fabry-Pérot interference and investigation of many interesting physical phenomena.
关键词： Ag/ITO/CoFeB/ITO/Ag layers,Hybrid Materials,Magnetic,Plasmonics,AAO substrate,Fabry-Pérot interference,Nanoporous thin film,Optical
更新于2025-09-10 09:29:36
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Epitaxial thin films as a model system for Li-ion conductivity in Li <sub/>4</sub> Ti <sub/>5</sub> O <sub/>12</sub>
摘要： Using an epitaxial thin-film model system deposited by pulsed laser deposition, we study Li-ion conductivity in Li4Ti5O12, a common anode material for Li-ion batteries. Epitaxy, phase purity, and film composition across the film thickness are verified employing out-of-plane and in-plane X-ray diffraction, transmission electron microscopy, time-of-flight mass spectrometry, and elastic recoil detection analysis, respectively. We find that epitaxial Li4Ti5O12 behaves like an ideal ionic conductor that is well described by a parallel RC equivalent circuit, with an ionic conductivity of 2.5·10-5 S/cm at 230 °C and an activation energy of 0.79 eV in the measured temperature range from 205 °C to 350 °C. Differently, in a co-deposited polycrystalline Li4Ti5O12 thin film with average in-plane grain size <10 nm, a more complex behavior with contributions from two distinct processes is observed. Ultimately, epitaxial Li4Ti5O12 thin films can be grown by pulsed laser deposition and reveal suitable transport properties for further implementation as zero-strain and grain boundary free anodes in future solid-state microbatteries design.
关键词： anode,polycrystalline,thin film,Li4Ti5O12,LTO,battery,epitaxial,PLD
更新于2025-09-10 09:29:36
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Microstructured SiOx thin films deposited from hexamethyldisilazane and hexamethyldisiloxane using atmospheric pressure thermal microplasma jet
摘要： Microstructured silicon oxide (SiOx) thin films were deposited on glass and metal substrates from 1,1,1,3,3,3-hexamethyldisilazane (HMDSN) and hexamethyldisiloxane (HMDSO) by using atmospheric-pressure thermal microplasma jet. Two kinds of string-like products, randomly bent string-like products and linear string-like products, were deposited and they formed microstructured films. The bent string-like products formed labyrinth-like structures and the linear string-like products lay in parallel to form a large aligned structure. The width of both the bent and linear string-like products was from 1 to 3 μm, regardless of the kind of the precursor but depending on the plasma irradiation conditions. The influence of various surface microstructure of substrates on the formation of the SiOx microstructure was investigated to make clear the mechanism for the formation of the microstructures.
关键词： Atmospheric pressure microplasma,Thin film,Microstructure,Silicon oxide
更新于2025-09-10 09:29:36
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Orientation and Morphology Control of Liquid Crystalline Block Copolymer Thin Film by Liquid Crystalline Solvent
摘要： The critical challenge to engineer the morphological structures in the strongly phase segregated block copolymer thin film is to overcome the preferential wetting of the blocks at interface and direct the self-assembly process. Herein, we utilize surface activity and selective solvation of a nematic (N) liquid crystalline (LC) solvent, 5CB, to facilely alter the LC anchoring and the orientation of the nano-phase separated structures of the smectic-nematic (S-N) LC block copolymer thin film. For the neat S-N diblock copolymer thin film, the nano-structures are parallel aligned. In contrast, with continuous introduction of 5CB into the system, the orientations of the characteristic nano-structures and the morphologies of the LC thin film can be consequently changed, yielding the perpendicularly oriented lamellar or cylindrical structures with the feature size below 10 nm. The homeotropic alignment of the 5CB nematics near the air interface plays a critical role to induce this unique behavior in the S-N/5CB systems, which offers an opportunity to fine-tune the interfacial structures and the morphological patterning in the block copolymer thin film.
关键词： Thin film,Self-assembly,5CB,Liquid crystalline block copolymer,Nano-structures
更新于2025-09-10 09:29:36
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Lectins at Interfaces—An Atomic Force Microscopy and Multi-Parameter-Surface Plasmon Resonance Study
摘要： Lectins are a diverse class of carbohydrate binding proteins with pivotal roles in cell communication and signaling in many (patho)physiologic processes in the human body, making them promising targets in drug development, for instance, in cancer or infectious diseases. Other applications of lectins employ their ability to recognize specific glycan epitopes in biosensors and glycan microarrays. While a lot of research has focused on lectin interaction with specific carbohydrates, the interaction potential of lectins with different types of surfaces has not been addressed extensively. Here, we screen the interaction of two specific plant lectins, Concanavalin A and Ulex Europaeus Agglutinin-I with different nanoscopic thin films. As a control, the same experiments were performed with Bovine Serum Albumin, a widely used marker for non-specific protein adsorption. In order to test the preferred type of interaction during adsorption, hydrophobic, hydrophilic and charged polymer films were explored, such as polystyrene, cellulose, N,-N,-N-trimethylchitosan chloride and gold, and characterized in terms of wettability, surface free energy, zeta potential and morphology. Atomic force microscopy images of surfaces after protein adsorption correlated very well with the observed mass of adsorbed protein. Surface plasmon resonance spectroscopy studies revealed low adsorbed amounts and slow kinetics for all of the investigated proteins for hydrophilic surfaces, making those resistant to non-specific interactions. As a consequence, they may serve as favorable supports for biosensors, since the use of blocking agents is not necessary.
关键词： lectin,gold,adsorption,bovine serum albumin,polystyrene,surface plasmon resonance spectroscopy,cellulose thin film
更新于2025-09-10 09:29:36