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[IEEE 2017 International Conference on Electron Devices and Solid-State Circuits (EDSSC) - Hsinchu (2017.10.18-2017.10.20)] 2017 International Conference on Electron Devices and Solid-State Circuits (EDSSC) - Influence of sensitization on the surface properties of PbSe thin films
摘要： This report focuses on the surface properties of sensitized polycrystalline lead selenide (PbSe) thin films that could significantly affect the final performance of photoconductive devices. By characterization the element chemical state and the current distribution along with the relevant morphologies at surface of sensitized and original PbSe films, it is confirmed that after sensitization surface properties, as well as the performance of photoconductive devices have been significantly modified. The mechanism was also discussed.
关键词： surface properties,lead selenide,photoconductive,sensitization
更新于2025-09-23 15:23:52
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Comparison of the Physicochemical Properties of TiO2 Thin Films Obtained by Magnetron Sputtering with Continuous and Pulsed Gas Flow
摘要： In this paper, a comparison of TiO2 thin ?lms prepared by magnetron sputtering with a continuous and pulsed gas ?ow was presented. Structural, surface, optical, and mechanical properties of deposited titanium dioxide coatings were analyzed with the use of a wide range of measurement techniques. It was found that thin ?lms deposited with a gas impulse had a nanocrystalline rutile structure instead of ?brous-like anatase obtained with a continuous gas ?ow. TiO2 thin ?lms deposited with both techniques were transparent in the visible wavelength range, however, a much higher refractive index and packing density were observed for coatings deposited by the pulsed gas technique. The application of a gas impulse improved the hardness and scratch resistance of the prepared TiO2 thin ?lms.
关键词： optical properties,scratch resistance,thin ?lms,gas impulse magnetron sputtering,microstructure,hardness,surface properties,mechanical properties,TiO2
更新于2025-09-23 15:21:21
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Optical, electrical, structural and magnetic properties of BiSe thin films produced by CBD on different substrates for optoelectronics applications
摘要： BiSe thin films have been grown on substrates as PMMA, ITO, glass and Si wafer by using chemical bath deposition (CBD) method. Deposition temperature and time and pH are kept to be constant during the production of the thin films. The thickness of BiSe thin films, which are produced on ITO, glass, PMMA and Si wafer substrate are 513, 468, 1039 and 260 nm, respectively. According to GAXRD results, the films, which are grown on glass and PMMA substrate, have amorphous structure, but, the films, which are grown on ITO and Si wafer substrate, have peaks of Bi2Se3 crystal. Grain sizes, crystallization number per unit area and dislocation density for ITO and Si wafer substrate are calculated as 112.40 nm and 43.04 nm; 2.25×10?5 and 7.91×10?5 (1/nm2), respectively. The contact angles and critical surface tension of distilled water, ethylene glycol, formamide and diiodamethane liquids for thin films grown on glass, ITO, PMMA and Si wafers were obtained by the Zisman method. The % transmittance and % reflectance values of thin films grown on glass, ITO, PMMA are calculated as % T: 79.90, 92.76 and 67.37; % R: 6.18, 2.07 and 10.59, respectively. Eg values of thin films grown on glass, ITO, PMMA are calculated as Eg=1.92; 2.18; 1.60 eV. The extinction coefficients, refractive indexes and relative dielectric constants of thin films grown on glass, ITO, PMMA are calculated as k=0.007; 0.002 and 0.012; n=1.65; 1.34 and 1.96; ε1=0.271; 0.083 and 0.528 respectively. Sheet resistance, hall mobility, sheet carrier densities, bulk carrier densities and conductivity types for glass, ITO, PMMA and Si are 6.52×107, 6.65×101, 1.09×108 and 6.45×102 (Ω/cm2); 2.38, 1.21×10?1, 5.34 and 1.52 (cm2/V.s); 4.01×1010, 7.71×1017, 1.06×1010 and 6.34×1015 (cm?2); 4.58×1014, 1.50×1022, 1.02×1014 and 2.89×1020 (cm?3); p, n, p and p, respectively. In addition, I–V characteristics and changes of magnetoresistance values versus magnetic field of the thin films are obtained by Van der Pauw method and HEMS.
关键词： magnetoresistance,thin film deposition,optical band gap,carrier density,surface properties,crystal growth
更新于2025-09-23 15:21:21
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[IEEE 2018 IEEE International Conference on Electrical Engineering and Photonics (EExPolytech) - Saint Petersburg, Russia (2018.10.22-2018.10.23)] 2018 IEEE International Conference on Electrical Engineering and Photonics (EExPolytech) - Porous Silicon as a Material for Nanocomposites and the Effect of its Parameters on the Morphology of Silver Clusters
摘要： On the example of the por-Si/Ag composites it is demonstrated the ability to control the morphology of the guest material (Ag) by changing the parameters of the porous media (por-Si). Two groups of key parameters of porous materials important for creating composites based on them are discussed. Porous silicon was obtained by electrochemical anodic etching. The introducing Ag into the pores was performed by the cathodic electrochemical deposition. It is observed the increasing the anodizing time is leads to the noticeably changes of wetting angle of por-Si, and, in turn, significantly affects the morphology of Ag clusters. The growth mechanisms of Ag clusters on the por-Si surface and the fields of its potential application are discussed.
关键词： porous texture,surface properties,porous silicon composites,por-Si/Ag composites,electrochemical deposition,surface functionality,silver clusters
更新于2025-09-23 15:19:57
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A Nanostructured Gold/Graphene Microfluidic Device for Direct and Plasmonic-Assisted Impedimetric Detection of Bacteria
摘要： Hierarchical 3D gold nano-micro islands (NMIs) are favourably structured for direct and probe-free capture of bacteria in optical and electrochemical sensors. Moreover, their unique plasmonic properties make them a suitable candidate for plasmonic-assisted electrochemical sensors, yet the charge transfer needs to be improved. In the present study, we propose a novel plasmonic-assisted electrochemical impedimetric detection platform based on hybrid structures of 3D gold NMIs and graphene (Gr) nanosheets for probe-free capture and label-free detection of bacteria. The inclusion of Gr nanosheets significantly improves the charge transfer, addressing the central issue of using 3D gold NMIs. Notably, the 3D gold NMIs/Gr detection platform successfully distinguishes between various types of bacteria including Escherichia coli (E. coli) K12, Pseudomonas putida (P. putida) and Staphylococcus epidermidis (S. epidermidis) when electrochemical impedance spectroscopy is applied under visible light. We show that distinguishable and label-free impedimetric detection is due to dissimilar electron charge transfer caused by various sizes, morphologies, and compositions of the cells. In addition, the finite-difference time-domain (FDTD) simulation of the electric field indicates the intensity of charge distribution at the edge of the NMI structures. Furthermore, the wettability studies demonstrated that contact angle is a characteristic feature of each type of captured bacteria on the 3D gold NMIs, which strongly depends on the shape, morphology, and size of the cells. Ultimately, exposing the platform to various dilutions of the three bacteria strains, revealed the ability to detect dilutions as low as ~20 CFU/mL in a wide linear range of detection of 2(cid:3)101-105, 2(cid:3)101-104 and 1(cid:3)102-1(cid:3)105 CFU/mL for E. coli, P. putida, and S. epidermidis, respectively. The proposed hybrid structure of 3D gold NMIs and Gr combined by novel plasmonic and conventional impedance spectroscopy techniques open interesting avenues in ultrasensitive label-free detection of bacteria with low cost and high stability.
关键词： Label-free bacteria detection,Hierarchical gold nano-micro islands,Surface properties,Impedance spectroscopy,plasmonic-assisted electrochemical detection platform
更新于2025-09-23 15:19:57
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Solution-processed organic field-effect transistors with cross-linked poly(4-vinylphenol)/polyvinyl alcohol bilayer dielectrics
摘要： A single-layer gate dielectric cannot meet the requirements of large permittivity (k) and low surface polarity for fabricating low-operating-voltage, high-performance OFETs. Here, we have designed a bilayer gate dielectric consisting of a low-k cross-linked poly(4-vinylphenol) (CL-PVP) in contact with an active layer to provide a low polar surface and an underneath high-k polyvinyl alcohol (PVA) layer to ensure a high capacitance. The results show that the CL-PVP/PVA bilayer not only offers a smooth and uniform surface with low polarity and low surface energy as well as good solvent resistance for efficient carrier transport, but also possesses a relatively high capacitance and low leakage current for low threshold and operating voltages. We have utilized this bilayer dielectric to fabricate OFETs based on a conventional semiconducting polymer poly(3-hexylthiophene) (P3HT). High overall device performances have been achieved in the devices with a mobility of 0.1 cm2V-1s-1. The maximum density of trap states at the interface between the P3HT film and the CL-PVP/PVA bilayer is estimated to be 7.10×1012 cm-2 eV-1, further proving that this bilayer dielectric provides a high quality interface for P3HT. The CL-PVP/PVA bilayer is thus a promising candidate as a gate dielectric for fabricating high-performance organic or even organic-inorganic hybrid perovskite transistors by a solution processing technique.
关键词： P3HT OFETs,gate dielectrics,low-k CL-PVP/high-k PVA bilayer,dielectric and surface properties
更新于2025-09-19 17:15:36
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Surface Properties of Beech Wood after CO2 Laser Engraving
摘要： The paper deals with the properties of a beech wood surface treated by CO2 laser engraving. The studied concerns were the discoloration, changes to morphology assessed through roughness and waviness parameters, and surface wetting with standard liquids (water and diiodomethane), with the aim of determining the wood surface free energy. The results have confirmed that the studied properties of the beech wood surface varied significantly, which were affected by the laser beam power P and raster density n. With increasing P and n, the lightness L* (expressed in CIE L*a*b* color space) decreased significantly. We also observed significant variation in the color coordinates a* and b*. At 8% laser power, the roughness and waviness parameters measured parallel as well as perpendicular to the grain increased proportionally with the increasing raster density. However, 4% laser power was not associated with distinct changes. Increasing the raster density reduced beech wood surface wetting equally with water and with diiodomethane. This was reflected in the higher contact angle values. The wood surface exhibited higher hydrophobicity at 4% laser power. At this power, the increasing raster density was reflected in the decreasing surface free energy, due to its polar component decrease. At 8% laser power, the changes in surface free energy were very minor from the practical viewpoint. The results suggest a potential good adhesion between film-forming materials and wood. However, the gluing performance may be negatively affected by the high roughness attained at 8% laser power and at higher raster densities.
关键词： color,wetting,surface properties,CO2 laser,roughness,contact angle,beech wood,surface free energy
更新于2025-09-19 17:13:59
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Time-frequency analysis of laser-excited surface acoustic waves based on synchrosqueezing transform
摘要： Laser-excited surface acoustic wave (LSAW) techniques can realize the measurement of surface properties through dispersion curve inversion. In addition to the conventional phase spectrum method, time-frequency analysis can also be used as a calculation tool for the dispersion curve. An accurate time-frequency analysis method is important in precisely inverting the surface properties. In this paper, synchrosqueezing transform (SST) is applied to the analysis of LSAW. By comparing the processing results of the constructed LSAW signal, SST shows higher time-frequency resolution and robustness than other common time-frequency analysis algorithms. Finite element model is used to simulate the propagation of LSAW in the film/substrate structure. And SST is used to calculate the dispersion curve of SAW information extracted during the simulation. A fast algorithm is introduced, where the film thickness is initially estimated by calculating the midrange. Through inversion, the resulting film thickness error is only 1.20% from the theoretical value. Therefore, SST is an effective tool for analyzing LSAW and calculating its dispersion curve.
关键词： Synchrosqueezing transform,Surface acoustic wave,Surface properties,Dispersion curve
更新于2025-09-19 17:13:59
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Investigation on the Surface Properties of 5A12 Aluminum Alloy after Nd: YAG Laser Cleaning
摘要： The surface of the aluminum alloy is prone to oxidation, which in turn a?ects the quality of the weld. The 5A12 aluminum alloy was cleaned by acousto-optic Q-switched diode-pumped Nd:YAG laser and the e?ects of di?erent laser powers and di?erent cleaning speeds on the surface roughness, microstructure, element content, microhardness, residual stress and corrosion resistance of aluminum alloy were investigated. The results show that when the power is 98W and the cleaning speed is 4.1 mm/s, the e?ect of Nd: YAG laser on the removal of oxide ?lm on 5A12 aluminum alloy surface is the most e?ective. After laser cleaning, the smoothness and strength of aluminum alloy surface can be e?ectively improved. However, as a major element in 5A12 aluminum alloy, the content of magnesium decreased. At the same time, the residual tensile stress was generated on the surface of the aluminum alloy after cleaning, and the corrosion resistance slightly decreased.
关键词： surface properties,5A12 aluminum alloy,laser cleaning
更新于2025-09-16 10:30:52
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Insights on the photocatalytic degradation processes supported by TiO2/WO3 systems. The case of ethanol and tetracycline
摘要： TiO2/WO3 composites are widely in the literature as engineered systems for photocatalytic and (photo)electrochemical applications, since the presence of WO3 can promote both visible light absorption and electron transfer phenomena of TiO2. The preparation of these system, depending on the preparation method, can also affect the surface feature with respect to TiO2, modifying adsorption and performance, as well as the reaction mechanisms. Here, TiO2/WO3 composites were prepared by precipitation of WO3 onto the TiO2 surface and characterized in terms of their structural, morphological, optical and surface properties. Raman and IR spectroscopy as well as a marked shift in the isoelectric point support the preferential surface location of WO3. Samples were photocatalytically tested towards the degradation of ethanol and of tetracycline and the adsorption and degradation behaviour were studied, suggesting, in both cases, significant variations of the reaction paths by the addition of WO3.
关键词： Surface properties,Photocatalytic oxidation,Tungsten oxide,Intermediates,Reaction mechanism
更新于2025-09-10 09:29:36