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Optical Characteristics of Strontium Titanate Films Obtained by the Sol–Gel Method
摘要： Using data of multiangle spectrophotometry and spectral ellipsometry in the UV and visible ranges, spectra of the refractive indices and absorption coefficients and width of the forbidden band of one- and five-layer strontium titanate films obtained by the sol–gel method have been calculated. Layer-by-layer deposition of sol on quartz substrates, from one to five layers, leads to an increase in film porosity from 4 to 33%. This causes a decrease in the refractive indices in the middle part of the visible spectrum from 2.33 to 1.87, which leads to a decrease in the reflectance and an increase in the transmittance or transparency of five-layer films. With an increase in the heating temperature of such films from 500 to 750°C, a shift of the absorption band maximum from 239 to 253 nm takes place and the optical width of the forbidden band decreases from 4.63 to 4.20 eV. The absorption band maximum of the single-layer film falls on the wavelength of 252 nm, and its optical width of the forbidden band is 3.96 eV.
关键词： Strontium titanate films,optical characteristics,forbidden band width,sol–gel method,refractive indices,absorption coefficients
更新于2025-09-09 09:28:46
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Mathematical Modeling of Droplet Formation, Evaporation, and Film Growth to Study Crystallite Size and Film Thickness of Spray Pyrolysis Deposited TiO<sub>2</sub> Thin Films
摘要： The pure TiO2 thin films were successfully deposited onto a glass substrate by using modified spray pyrolysis system. The TiO2 thin films were deposited at temperature 350?C using Titanium trichloride precursor solutions of concentration 0.075 M, 0.1 M, and 0.125 M. Also, TiO2 thin films with precursor solutions of concentration 0.1 M were deposited at different deposition temperature 350?C, 400?C, and 450?C. The prepared samples were further annealed at 500?C for 2 h to improve crystallinity. The XRD study revealed that the deposited TiO2 thin films were polycrystalline and showed anatase phase with pre-dominant (101) peak. The crystallite size calculated from XRD was found to increase with increase in precursor solution concentration. The mathematical model to calculate crystallite size and film thickness were developed and the predicted results were compared with experimental results. The experimentally calculated crystallite size and thickness was in good agreement with the predicted results. The details of mathematical model and calculations TiO2 thin films for were discussed in detail.
关键词： Growth,Liquid phase epitaxy,Crystallization,Titanium oxide,X-ray diffraction,Semiconducting films
更新于2025-09-09 09:28:46
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Electrophoretic Deposition Fabrication and Magnetic Manipulation of Magnetic Semiconductor Films
摘要： ZnO:Co semiconductor films were synthesized by a two-step electrophoretic deposition method. Various morphologies, including solid, crystal-grain or nanorod-array film, could be obtained by tuning the deposition conditions. Careful characterizations indicate the morphologies and structures have great effect on the magnetic and optical properties of the films. Significant difference of magnetism was investigated in the films prepared under different deposition potentials. The origination of the magnetism difference and the mechanism of the electrophoretic deposition were discussed.
关键词： Electrophoretic deposition,Magnetic semiconductor films,Nanorod arrays,Magnetism difference
更新于2025-09-09 09:28:46
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A comprehensive review on thin film-based nano-biosensor for uric acid determination: arthritis diagnosis
摘要： This article aims to provide a survey on the development of thin film-based nano-biosensor over the decade, which includes sensing principles, electrode types and various thin film matrices. The theoretical and experimental results suggest that the thin film-based sensor are suitable for highly sensitive detection of low concentration bio molecules and can be used for early diagnosis and screening of arthritis, kidney diseases and other cardiovascular diseases. This review concludes that enzyme immobilisation and surface functionalisation methods were used to increase sensitivity of the biosensor and new combination of polymer nano-composites with metal oxide thin films results in increased efficiency due to its high biocompatibility.
关键词： nanomaterials,enzymes,thin films,uric acid,immobilisation,biocompatibility
更新于2025-09-09 09:28:46
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Electrochemical Behavior of Titanium Nitride Thin Films Deposited on Silicon by Plasma Discharge Technique in Cathodic Cage
摘要： Titanium nitride films were deposited on silicon by plasma discharge in cathodic cage with holes and without holes on the sides. Each film was deposited with a pressure of 253 Pa, treatment time of 2 h, and at diverse conditions of temperature and gas flow of N2 and H2. The electrochemical polarization and electrochemical impedance techniques were used to understand the effect on the electrochemical properties of these films in relation to the presence or absence of holes on the sides of the cathodic cage and to investigate the electrochemical behavior of the films formed, which presented as both capacitive and resistive for the conditions analyzed.
关键词： thin films,cathodic cage,polarization,titanium nitride,EIS
更新于2025-09-09 09:28:46
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Effects of Aging on Chlorinated Plasma Polymers
摘要： Thin films deposited from propanol-chloroform-argon mixtures by plasma enhanced chemical vapor deposition at different partial pressures of chloroform in the feed, CCl, were characterized after two years of aging and their characteristics compared with their as-deposited properties. Film thickness decreased and surface roughness increased with aging. Surface contact angles also increased with aging for the chlorinated films. For the film deposited with 40% chloroform in the feed the contact angle increased about 14°. Transmission infrared and Energy dispersive X-ray spectroscopy revealed that the films gain carbonyl and hydroxyl groups and lose chlorine and hydrogen on aging. Chlorination appears to make the films more durable. Delamination was observed for the unchlorinated films.
关键词： contact angle,stability,thin films,IRS,a-C:H:O:Cl
更新于2025-09-09 09:28:46
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Physical Vapor Deposited Films of a Perylene Derivative: Supramolecular Arrangement and Thermal Stability
摘要： The analysis of supramolecular arrangement is essential to understand the role of this key factor on the optical and electrical properties of organic thin films. In this work, thin solid films of bis(phenethylimido) perylene (PhPTCD) fabricated using physical vapor deposition (PVD) technique (thermal evaporation), deposited simultaneously onto different substrates (Ag mirror, Ge, and quartz plates) contingent on the characterization technique. The main objective is to study the PhPTCD supramolecular arrangement and the thermal stability of this arrangement in PVD films. The ultraviolet-visible absorption reveals a controlled growth of the PVD films, and the micro-Raman scattering data show that the PhPTCD molecule is not thermally degraded in the conditions of these experiments. The microscopy also shows a homogeneous morphological surface of the PVD film at macro and micro scales, with molecular aggregates at nanoscale. Besides, the PVD film roughness does not follow substrate roughness. The X-ray diffraction indicates a crystalline structure for PhPTCD powder and an amorphous form for PhPTCD PVD film. The infrared absorption spectroscopy points to a preferential flat-on organization of the molecules in the PVD films. In addition, the annealing process (200 oC for 20 minutes) does not affect the supramolecular arrangement of the PhPTCD PVD films.
关键词： perylene,PVD nanostructured films,thermal treatment,supramolecular arrangement
更新于2025-09-09 09:28:46
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Structural, optical and electrical properties of reactively sputtered CrxNy films: Nitrogen influence on the phase formation
摘要： The properties of various CrxNy films grown by direct current (DC) reactive sputtering process with different values of nitrogen partial pressures (0, 2×10-4, 3.5×10-4 and 5×10-4 mbar) were studied. The structural analysis of the samples was performed by using X-ray diffraction and transmission electron microscopy (TEM), while an elemental analysis was realized by means of Rutherford backscattering spectrometry. By varying nitrogen partial pressure the pure Cr layer, mixture of Cr, Cr2N and CrN phases, or single-phase CrN was produced. TEM analysis showed that at pN2 = 2×10-4 mbar the layer has dense microstructure. On the other hand, the layer deposited at the highest nitrogen partial pressure exhibits pronounced columnar structure. The optical properties of CrxNy films were evaluated from spectroscopic ellipsometry data by the Drude or combined Drude and Tauc-Lorentz model. It was found that both refractive index and extinction coefficient are strongly dependent on the dominant phase formation (Cr, Cr2N, CrN) during the deposition process. Finally, the electrical studies indicated the metallic character of Cr2N phase and semiconducting behaviour of CrN.
关键词： spectroscopic ellipsometry,thin films,chromium nitrides,electrical properties,microstructure
更新于2025-09-09 09:28:46
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Porous Multilayered Films Based on poly(3,4- ethylenedioxythiophene) and poly(indole-5-carboxylic acid) and Their Capacitance Performance
摘要： Layer-by-layer (LBL) technique is a prevalent way to construct multilayered films. Herein, using high conducting poly(3,4-ethylenedioxythiophene) (PEDOT) and good stable redox-active poly(indole-5-carboxylic acid) (5-PICA), an alternately multilayered porous films has been prepared by the electrochemical LBL method. The alternately multilayered films were characterized by scanning electron microscope (SEM), cyclic voltammetry (CV), galvanostatic charge-discharge (CD) and electrochemical impedance spectroscope (EIS) techniques. Compared with monolayered PEDOT (147.8 F g-1) and 5-PICA(198.3 F g-1), the PEDOT/5-PICA/PEDOT/5-PICA 4-layered film exhibited a higher specific capacitance which reached 281.7 F g-1 at 20 A g-1 in 1.0 M H2SO4 solution. Furthermore, the specific capacitance of 4-layered film still had good stability, viz., 73% retention after 1000 cycles at the range of potential -0.15 to 1.0 V and even reached 95% if the potential range was from -0.15 to 0.8 V. Therefore, these results indicated that the PEDOT/5-PICA/PEDOT/5-PICA was a potential electrode material for supercapacitors.
关键词： Specific capacitance,Layer-by-layer films,Electropolymerization,Conducting polymers
更新于2025-09-09 09:28:46
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Extremely Light Carrier‐Effective Mass in a Distorted Simple Metal Oxide
摘要： Exotic electron transport properties such as quasi 1D conductivity are useful to realize advanced electronic devices showing unique properties. Anisotropic electron transport properties are often found in complex metal oxides due to their complicated crystal structures. Although simple metal oxides with distorted crystal structures could also be expected to show anisotropic electron transport properties, it is rarely studied most likely due to the lack of their high-quality epitaxial films. Here anisotropic electron transport properties, showing “fast electron transport path,” in a simple distorted metal oxide, NbO2, is reported. High-quality NbO2 epitaxial films with different crystallographic orientations on (0001) and (11102) α-Al2O3 single crystal substrates are fabricated, and the electron transport properties at room temperature are measured. Both the resistivity and absolute value of the thermopower along the [112] NbO2 is pretty small as compared with other directions. Experimentally obtained electron carrier effective mass in the [112] direction is surprisingly small, only 0.051 me, which is similar to that of high-mobility GaAs. Since simple metal oxides have several advantages against complex oxides in view of easy fabrication, the present results will be beneficial for realizing advanced electronic devices using simple metal oxides.
关键词： distorted simple metal oxide,NbO2,epitaxial films,carrier effective mass,anisotropic electron transport
更新于2025-09-09 09:28:46