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<i>C–V–f, G–V–f</i> and <i>Z″–Z′</i> Characteristics of <i>n</i> -Type Si/B-Doped <i>p</i> -Type Ultrananocrystalline Diamond Heterojunctions Formed via Pulsed Laser Deposition
摘要： n-Type Si/p-type B-doped ultrananocrystalline diamond heterojunction photodiodes were built using pulsed laser deposition at a heated substrate temperature of 550 °C. Following the capacitance–voltage–frequency (C–V–f) and conductance–voltage–frequency (G–V–f) plots, the series resistance (Rs) values at zero bias voltage were 154.41 Ω at 2 MHz and 1.72 kΩ at 40 kHz. Rs should be ascribed to Rs occurring in the metallic contact and the bulk resistance in the active layer. At 40 kHz, the interface state density (Nss) was 1.78 × 10^13 eV^?1 cm^?2 and dropped exponentially to 1.39 × 10^12 eV^?1 cm^?2 at 2 MHz. An assessed Nss occurring at the heterojunction interface was the cause of deterioration in the photo-detection properties. At different V values, the appearance of the real (Z') and imaginary (Z'') characteristic curves revealed single semicircles whose centers lay below the Z' axis. The magnitude of the curve was diminished with the increment of V. The particularities of Z''–Z' plots can be identified as an equivalent circuit model. The appropriate model included Rs, which was combined with the parallel circuit of resistance and constant phase element.
关键词： UNCD,Interface State Density,Series Resistance,PLD,Impedance
更新于2025-11-14 17:28:48
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Composition and Strain Evolution of Undoped Si <sub/>0.8</sub> Ge <sub/>0.2</sub> Layers Submitted to UV-Nanosecond Laser Annealing
摘要： Ultraviolet Nanosecond Laser Annealing (UV-NLA, XeCl laser, 308 nm, 145 ns) was performed on 30 nm-thick Si0.8Ge0.2 epitaxial layers. The various regimes encountered after single pulse UV-NLA are described and discussed, including submelt, SiGe layer partial and total melt, as well as melt beyond the SiGe epi-layer. Energy densities around 2.00 J/cm2 and above led to the formation of pseudomorphic layers with strong Ge redistribution. Starting from uniform Si0.8Ge0.2 layers, Ge segregation towards the surface resulted in the formation of a Ge-rich surface layer with up to 55% Ge for 2.00 J/cm2. Such pseudomorphic SiGe layers with graded composition and a Ge-rich surface layer may find some promising applications such as contact resistance lowering in doped layers.
关键词： SiGe,pseudomorphic,contact resistance,Ge redistribution,Ultraviolet Nanosecond Laser Annealing
更新于2025-11-14 14:32:36
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Scaling of High-Performance Organic Permeable Base Transistors
摘要： Organic permeable-base transistors (OPBTs) show potential for high-speed, flexible electronics. Scaling laws of OPBTs are discussed and it is shown that OPBT performance can be increased by reducing their effective device area. Comparing the performance of optimized OPBTs with state-of-the-art organic field-effect transistors (OFETs), it is shown that OPBTs have a higher potential for an increased transit frequency. Not only do OPBTs reach higher transconductance values without the need for sophisticated structuring techniques, but they are also less sensitive to parasitic contact resistances. With the help of a 2D numerical model, the reduced contact resistances of OPBTs are explained by a homogeneous injection of current across the entire emitter electrode, compared to injection in a small area along the edge of the source of OFETs.
关键词： scaling,injection,organic permeable-base transistors,contact resistance,transit frequency
更新于2025-10-22 19:50:37
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Effect of front TCO on the performance of rear-junction silicon heterojunction solar cells: Insights from simulations and experiments
摘要： In this study we make a detailed comparison between indium tin oxide (ITO), aluminum-doped zinc oxide (ZnO:Al) and hydrogenated indium oxide (IO:H) when applied on the illuminated side of rear-junction silicon heterojunction (SHJ) solar cells. ITO being the state of the art material for this application, ZnO:Al being an attractive substitute due to its cost effectiveness and IO:H being a transparent conductive oxide (TCO) with high-mobility and excellent optical properties. Through numerical simulations, the optically optimal thicknesses for a double layer anti-reflective coating system, consisting of the respective TCO and amorphous silicon oxide (a-SiO2) capping layers are defined. Through two-dimensional electrical simulations, we present a comparison between front-junction and rear-junction devices to show the behavior of series resistance (Rs) in dependence of the TCO sheet resistance (Rsh) and the device effective lifetime (τeff). The study indicates that there is a τeff dependent critical TCO Rsh value, above which, the rear-junction device will become advantageous over the front-junction design in terms of Rs. Solar cells with the respective layers are analyzed. We show that a thinner TCO optimized layer will result in a benefit in cell performance when implementing a double layer anti-reflective coating. We conclude that for a highest efficiency solar cell performance, a high mobility TCO, like IO:H, is required as the device simulations show. However, the rear-junction solar cell design permits the implementation of a lower conductive TCO in the example of the cost-effective ZnO:Al with comparable performance to the ITO, opening the possibility for substitution in mass production.
关键词： Transparent conductive oxide,Sheet resistance,Series resistance,Rear-junction,Silicon heterojunction,Anti-reflective coating
更新于2025-10-22 19:40:53
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Versatile Processing of Metal-Organic Framework-Fluoropolymer Composite Inks with Chemical Resistance and Sensor Applications
摘要： We report a new class of MOF inks with a water-repellent, photocurable fluoropolymer (PFPE) having up to 90 wt% MOF loading. These MOF inks enable to process various MOFs through spray coating, pen writing, stencil printing, and moulding at room temperature. Upon UV-curing, the hydrophobic PFPE matrix efficiently blocks water permeation but allows accessibility of chemicals into MOF pores, thereby freeing the MOF to perform its unique function. Moreover, by introducing functional MOFs we successfully demonstrated a water-tolerant chemosensor for a class of aromatic pollutants in water and a chemical-resistant thermosensor for visualizing temperature image. This approach would open up innumerable opportunities for those MOFs that are otherwise dormant.
关键词： MOF-polymer composite,Chemosensor,MOF processing,Thermosensor,Metal-Organic Framework,Chemical resistance
更新于2025-09-23 15:23:52
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Effect of O <sub/>2</sub> Flow Rate on Properties of Mn–SnO <sub/>2</sub> /Ag/Mn–SnO <sub/>2</sub> Multilayer Film
摘要： Multilayer films with Mn–SnO2 (MTO)/Ag/Mn–SnO2 (MTO) hybrid structure were prepared on a flexible polyethylene terephthalate (PET) substrate using a DC/RF sputtering system at room temperature. The optical, electrical, and structural properties of the thus-synthesized multilayer films were systematically investigated as a function of the O2/(Ar + O2) flow rate. The transmittance of the MTO/Ag/MTO multilayer films at 550 nm increased gradually from 83.1% to 87.9% and the sheet resistance (Rs) of the multilayer films increased from 6.3 to 9.8 Ω/sq upon increasing the O2/(Ar + O2) flow rate. The highest figure of merit (ΦTC) of the MTO/Ag/MTO multilayer film was 45.7 × 10?3 Ω?1 at an O2/(Ar + O2) flow rate of 2.8%. X-ray photoelectron spectra of multilayer films obtained with different O2/(Ar + O2) flow rates showed no noticeable variation.
关键词： Sheet Resistance,Figure of Merit,Transmittance,Gas Mixture Rate,Oxide/Metal/Oxide Structure
更新于2025-09-23 15:23:52
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Fabrication and photocatalytic performance evaluation of hydrodynamic erosion–resistant nano-TiO2–silicone resin composite films
摘要： Herein, we present the preparation of nano-TiO2–silicone resin composite films by double liquid phase spray deposition. The films exhibit better adhesion stability and photocatalytic activity under a hydrodynamic erosion condition than conventional nano-TiO2 composite films. The TiO2 layer morphology and effective TiO2 coverage ratio (CR) were affected by the initial curing time (ICT) of the silicone resin, e.g., the increase in an ICT from 10 to 40 min resulted in a CR change from 79.1 to 98.7%. The surface morphology evolution of composite films was studied under a hydrodynamic erosion period of 4 weeks. Obtained results allowed the 4-week evolution to be divided into four stages (pitting, crack pregnant, banded stripping, and surface stripping periods), additionally revealed that the CR of all samples was remained above 65%. The photocatalytic activity of composite films before and after 4-week hydrodynamic erosion was evaluated by rhodamine B degradation experiments. The 4-week erosion only led to the decrease of the photodegradation efficiencies by less than 40% in all cases. Thus, the fabricated TiO2–silicone composite films demonstrated excellent durability and photocatalytic activity under the conditions of long-term hydrodynamic erosion, allowing one to conclude that this work paves the way to the fabrication of next-generation photocatalytic materials for industrial applications.
关键词： Photocatalysis,Film formation mechanism,Silicone resin,Photodegradation,Hydrodynamic erosion resistance,Nano-TiO2
更新于2025-09-23 15:23:52
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Elaboration of a Conductive Textile by Coating for Clothes Equipped with Fourth-Generation Photovoltaic Cells
摘要： Conducting polymer coated in textiles possess a wide range of electrical properties. The surface resistivity is influenced by concentrations of the reactants, thickness of the coating, nature of the substrate surface, extent of penetration of the polymer into the textile structure and the strength of the binding of the coating to the textile surface. Low resistivity in fabric results from highly doped thicker coatings that penetrate well into the textile structure thus enabling good electrical contact between fibers. In this study, we had chosen copper as conductor polymer for coating. The electrical conductivity is influenced by the thickness of coating paste, the nature of the substrate surface. The thickness of the paste and the concentration of the copper were studied in this paper. Furthermore, the electrical surface resistance decreased from 68 MΩ to 8 MΩ with decreasing in coating thickness. However, the thickness of coated fabric is very important factor to determine conductivity and application of textile. In addition, we had noticed that the airflow is affected by the coating thickness which the penetration of the airflow differs from the lower thickness to the higher one. This study confirm that we can use coating woven fabric to develop a textile substrate responding to characteristics such as electrical resistance, drapability, air permeability and tensile strength, which are particularly important to be used as a support for flexible photovoltaic cells in clothes.
关键词： Conductor textile,Technical textile,Coating,Electrical resistance
更新于2025-09-23 15:23:52
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Investigation of nanomechanical and adhesion behavior for AlN coating and AlN/Fe2-3N composite coatings created by Active Screen Plasma Nitriding on Al 1050
摘要： This study investigated the effect of nitriding time and temperature on the mechanical properties of the composite AlN/Fe2-3N coating deposited on the pure aluminium substrate using the novel Active Screen Plasma Nitriding (ASPN) method. ASPN treatment was performed for 2, 5, 10, 15 h at temperatures of 450,500, and 550 (cid:1)C and Conventional Plasma Nitriding (CPN) treatment was carried out for 5 h at 500 (cid:1)C. All treatments were performed at the 10 KHz frequency with 80% duty cycle on the Al1050 substrate under 20%H2t80%N2 atmosphere. Phase and microstructure studies were performed using, respectively, the grazing incidence x-ray diffraction (GIXRD) system and the ?eld emission - scanning electron microscopy (FE-SEM) system equipped with energy-dispersive spectroscopy (EDS) analyzer. The mechanical strength of the coating was evaluated by the roughness, nano-hardness, nano-scratch, and adhesion strength tests performed on coated and uncoated specimens. According to the results, the uncoated Al1050 specimen, the CPN-treated specimen, and the ASPN-treated specimen had a mean nano-hardness of 0.7 ± 0.1 GPa, 10.9 ± 0.6 GPa, and 9.6 ± 0.5 GPa, respectively. It was also found that the single-phase AlN coating has a better adhesion strength and scratch strength (LC3 ? 12 N) than the composite AlN/Fe2-3N coating (LC3 ? 10 N). Examination of scratch mechanisms in hard AlN and AlN t Fe2-3N coatings deposited on a soft aluminium substrate showed that the failures in these coatings are due to tensile-type Hertzian cracks. However, as the load increases, the substrate undergoes increasing deformation and failures shift to chipping and interfacial spallation.
关键词： Adhesion strength,Active screen plasma nitriding,Pure aluminium,Conventional plasma nitriding,Scratch resistance,Nanoindentation
更新于2025-09-23 15:23:52
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Engineering organic electrochemical transistor (OECT) to be sensitive cell-based biosensor through tuning of channel area
摘要： The barrier integrity of epithelial tissue is crucial to many physiological functions in multicellular organisms. Hence, several scientific techniques, such as epithelial voltohmmeter (EVOM) and electric cell-substrate impedance sensing (ECIS), were developed to assess barrier function for in vitro assays. Organic electrochemical transistor (OECT), in particular, outperforms many biosensors because of its multiple advantages such as high transconductance, mixed ionic-electronic conductivity and high biocompatibility. Despite its extensive application in cell impedance sensing, little was reported on how its geometrical dimensions would affect the device performance and quality of cell-based measurement. In this work, OECTs in different dimensions were fabricated and characterized. Specifically investigated were their time and frequency responses towards the presence of epithelial cells (i.e. tightly packed colorectal adenocarcinoma cell line caco-2 and a novel leaky nasopharyngeal carcinoma cell line NPC43). Results show that the sensitivity of cell-based measurement is closely related to the impedance of the whole cell-OECT system. The performance of cell-based sensor would be affected by the tightness of target cell and can be tuned by controlling the active area of OECT.
关键词： Conducting polymer,Frequency response,Biosensor,Impedance spectroscopy,Transepithelial electrical resistance,Organic electrochemical transistor
更新于2025-09-23 15:23:52