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A supramolecular Cd( <scp>ii</scp> )-metallogel: an efficient semiconductive electronic device
摘要： A sonication-based strategy for the synthesis of a functional supramolecular Cd(II)-metallogel (CdA-OX) has been achieved through mixing cadmium(II) acetate dihydrate and oxalic acid dihydrate, a low molecular weight gelator (LMWG), in N,N-dimethyl formamide solvent at room temperature under atmospheric pressure. The mechanical properties of the supramolecular Cd(II)-metallogel were investigated through a rheological study. The pebble-like self-assembly hierarchical architecture of the supramolecular metallohydrogel was visualized through field emission scanning electron microscopy investigations. The electrical properties of the metallogel were thoroughly examined and indicate its semiconducting nature. Based on its conducting properties, the Cd(II)-metallogel was successfully applied to a Schottky barrier diode. Overall, this work is a novel instance of technologically challenging electronic device application of a Cd(II)-metallogel.
关键词： Schottky barrier diode,supramolecular Cd(II)-metallogel,sonication-based synthesis,electronic device,semiconducting nature
更新于2025-11-21 11:18:25
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Thinning ferroelectric films for high-efficiency photovoltaics based on the Schottky barrier effect
摘要： Achieving high power conversion efficiencies (PCEs) in ferroelectric photovoltaics (PVs) is a longstanding challenge. Although recently ferroelectric thick films, composite films, and bulk crystals have all been demonstrated to exhibit PCEs >1%, these systems still suffer from severe recombination because of the fundamentally low conductivities of ferroelectrics. Further improvement of PCEs may therefore rely on thickness reduction if the reduced recombination could overcompensate for the loss in light absorption. Here, a PCE of up to 2.49% (under 365-nm ultraviolet illumination) was demonstrated in a 12-nm Pb(Zr0.2Ti0.8)O3 (PZT) ultrathin film. The strategy to realize such a high PCE consists of reducing the film thickness to be comparable with the depletion width, which can simultaneously suppress recombination and lower the series resistance. The basis of our strategy lies in the fact that the PV effect originates from the interfacial Schottky barriers, which is revealed by measuring and modeling the thickness-dependent PV characteristics. In addition, the Schottky barrier parameters (particularly the depletion width) are evaluated by investigating the thickness-dependent ferroelectric, dielectric and conduction properties. Our study therefore provides an effective strategy to obtain high-efficiency ferroelectric PVs and demonstrates the great potential of ferroelectrics for use in ultrathin-film PV devices.
关键词： power conversion efficiency,Schottky barrier effect,ferroelectric photovoltaics,PZT ultrathin film,depletion width
更新于2025-11-14 17:28:48
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Switchable Schottky contacts: Simultaneously enhanced output current and reduced leakage current
摘要： Metal-semiconductor contacts are key components of nanoelectronics and atomic-scale integrated circuits. In these components Schottky diodes provide a low forward voltage and a very fast switching rate but suffer the drawback of a high reverse leakage current. Improvement of the reverse bias characteristics without degrading performance of the diode at positive voltages is deemed physically impossible for conventional silicon-based Schottky diodes. However, in this work we propose that this design challenge can be overcome in the organic-based diodes by utilizing reversible transitions between distinct adsorption states of organic molecules on metal surfaces. Motivated by previous experimental observations of controllable adsorption conformations of anthradithiophene on Cu(111), herein we use density functional theory simulations to demonstrate the distinct Schottky barrier heights of the two adsorption states. The higher Schottky barrier of the reverse bias induced by chemisorbed state results in low leakage current; while the lower barrier of the forward bias induced by physisorbed state yields a larger output current. The rectifying behaviors are further supported by nonequilibrium Green's function transport calculations.
关键词： van der Waals forces,Schottky contacts,Schottky barrier height,reverse leakage current,bistable state
更新于2025-09-23 15:23:52
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The current-voltage characteristics of the ferroelectric p-YMnO3 thin film/bulk p-Si heterojunction over a broad measurement temperature range
摘要： The reverse and forward bias I-V characteristics of the Al/p-YMO/p-Si/Al heterojunction were measured at room temperature (RT) and over temperature range, from 50 to 320 K, and the I-V curves showed Schottky diode-like characteristics. The ideality factor and barrier height values were calculated as 0.81 and 2.62 from the forward bias I-V curve at room temperature (300 K), respectively. The YMO powder was prepared via solid state reaction technique. YMO thin films were grown on front surface of p-Si substrate by radio frequency (rf) magnetron sputtering using a polycrystalline YMO single target. The YMO thin film thickness on Si substrate was measured as ~70 nm via Dektak XT surface profilometer. The XRD, SEM, UV-Vis and XPS measurements of the YMO thin film were also performed. The bandgap energy of YMnO3 thin films was determined as 2.10 eV by UV-vis. The temperature-dependent reverse and forward bias I-V curves were evaluated in terms of thermionic emission (TE), Schottky emission, Fowler-Nordheim (F-N) tunneling and space charge-limited current (SCLC) current theories. Furthermore, it has been seen that the forward bias conduction in the junction at each temperature obeys F-N tunneling because of the linearity in the ln (I/V2) versus V-1 curves.
关键词： Polycrystalline,Heterojunction,Ferroelectric,Al/p-YMO/p-Si/Al,Schottky barrier,YMnO3,Temperature dependent current characteristics
更新于2025-09-23 15:23:52
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One-Step Solvothermal Formation of Pt Nanoparticles Decorated Pt <sup>2+</sup> -Doped α-Fe <sub/>2</sub> O <sub/>3</sub> Nanoplates with Enhanced Photocatalytic O <sub/>2</sub> Evolution
摘要： The photooxidation of water into O2 has been identified as the barrier of water-splitting, and light-driven water oxidation catalysts have been intensively explored to develop highly active water splitting materials. Despite the fascinating advantages for photocatalytic water oxidation, such as abundance in nature, inexpensiveness, low toxicity, thermo/photo-stability, and suitable electronic band structures, hematite α-Fe2O3 is a poor photocatalyst for water oxidation due to its short exciton lifetime and hole diffusion length, weak carrier mobility and shallow sunlight penetration depth. In this work, we have synthesized Pt nanoparticles decorated Pt2+-doped α-Fe2O3 nanoplates (Pt/Pt-Fe2O3 NPs) by a one-step solvothermal route, which exhibit the enhanced photoactivity and photostablity for water oxidation. The introduction of the Pt into the α-Fe2O3 by the means of elemental doping and nanoparticle decoration accounts for the enhanced performance. The doping of Pt2+ into α-Fe2O3 improves the isolation efficiency of the photo-induced carriers which remarkably increases the lifespan of hole carriers, and the adherence of metal Pt nanoparticles to the surface of α-Fe2O3 leads to formation of schottky barriers at the interface which effectively impedes the combination of photo-generated electrons and holes.
关键词： photocatalytic O2 evolution,Pt nanoparticles decoration,Pt2+ doping,schottky barrier,α-Fe2O3 nanoplates
更新于2025-09-23 15:23:52
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On-chip sensor solution for hydrogen gas detection with the anodic niobium-oxide nanorod arrays
摘要： Two types of anodic niobium-oxide nanofilms were synthesized via anodization of an Al/Nb bilayer sputter-deposited onto a SiO2-coated Si wafer. Type I nanofilm was composed of a 200 nm thick NbO2 layer holding the upright-standing 650 nm long, 50 nm wide, and 70 nm spaced Nb2O5 nanorods, of 7·109 cm?2 density, whereas the Type II nanofilm had similarly long but bigger Nb2O5 nanorods, 100 nm wide, 220 nm spaced, and of 8·108 cm?2 density, aligned directly on a niobium metal without any buffering oxide layer, which was achieved for the first time. Each film was then incorporated in an advanced 3-D architecture and multilayer layout on a silicon chip comprising 33 microsensors, with variable sizes and tuned electrical characteristics, by combining the high-temperature vacuum or air annealing, sputter-deposition, and lift-off photolithography to form Pt/NiCr top electrodes and a multifunctional SiO2 interlayer, chemical etching, laser dicing, and ultrasonic wire-bonding. The proposed on-chip sensor solution allowed for a sensitive, fast, and highly selective (toward NH3 and CH4) detection of hydrogen gas. Comprehensive gas sensing tests performed for Type II nanofilm ultimately confirmed the presence of a Schottky-type sensing mechanism, the contribution, however, being substantially weaker than that due to reactions over the surface of the oxide nanorods, especially when the rods show a transition from fully to partially depleted states when interacting with H2 gas. The film formation and chip fabrication technologies may be transferable to other PAA-assisted 1-dimensional metal-oxide nanomaterials suitable for on-chip gas sensing.
关键词： niobium oxide nanorods,anodic alumina,hydrogen,Schottky barrier,anodizing,on-chip sensor
更新于2025-09-23 15:23:52
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A novel GaN-based lateral SBD with a TUG-AlGaN/GaN heterojunction
摘要： In this study, a novel GaN-based lateral Schottky barrier diode (SBD) with a thin upward graded AlGaN (TUG-AlGaN) barrier layer is proposed and investigated. The TUG-AlGaN layer upward graded from 0 to 0.50 mole fraction is used to replace the thick AlGaN layer of the heterojunction, which can reduce the distance from the 2-D electron gas (2DEG) to the Anode electrode, retain high density of 2DEG near the heterojunction, and eliminate the abrupt AlGaN/GaN conduction band offset at same time, subsequently can reduce the turn-on voltage and on-state voltage. The simulated results show that compared with the conventional SBD (with 25 nm Al0.23Ga0.77N layer), the proposed SBD achieves 0.32V reduction in turn-on voltage, and 1.21V reduction in on-state voltage. Meanwhile, although the proposed SBD doesn’t deliver obvious improvement in static characteristics when compared with the GaN-Based lateral field-effect rectifier (L-FER) (with 25 nm Al0.23Ga0.77N layer), the reverse recovery time of the proposed SBD is much smaller than that of the L-FER (with 25 nm Al0.23Ga0.77N layer). The outstanding static characteristics combined with excellent switching characteristics reveal its great potential for future power applications.
关键词： turn-on voltage,switching characteristics,thin upward graded AlGaN barrier layer,GaN-based lateral Schottky barrier diode
更新于2025-09-23 15:22:29
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Reverse bias-dependence of schottky barrier height on silicon carbide: influence of the temperature and donor concentration
摘要： The work deals with the dependences of the Schottky barrier height (SBH) on the reverse bias voltage, temperature and on donor concentration of metal/4H-SiC Schottky diodes. Using the tunneling modeling we have shown that the Schottky barrier height on silicon carbide strongly depends on the reverse bias voltage, temperature and doping concentration. At room temperature, the Schottky barrier height increases with increasing the reverse bias voltage at high doping concentration (about 1016 cm-3), while, at low doping concentration (about 1015 cm-3) the Schottky barrier height decreases with increasing the reverse bias voltage. These behaviors are independent of the Schottky barrier lowering effect. That means other effects occur at the barrier and depend on the reverse applied bias. The barrier height increases with increasing temperature and doping concentration under reverse bias conditions. The barrier heights extracted from the Padovani-Stratton formulas are close to the barrier heights extracted from the Tsu-Esaki formula in particular for the thermionic-field emission.
关键词： Reverse Bias,Silicon Carbide,Extraction,Tunneling,Schottky Barrier Height
更新于2025-09-23 15:22:29
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An Overview of the Ultrawide Bandgap Ga2O3 Semiconductor-Based Schottky Barrier Diode for Power Electronics Application
摘要： Gallium oxide (Ga2O3) is a new semiconductor material which has the advantage of ultrawide bandgap, high breakdown electric field, and large Baliga’s figure of merit (BFOM), so it is a promising candidate for the next-generation high-power devices including Schottky barrier diode (SBD). In this paper, the basic physical properties of Ga2O3 semiconductor have been analyzed. And the recent investigations on the Ga2O3-based SBD have been reviewed. Meanwhile, various methods for improving the performances including breakdown voltage and on-resistance have been summarized and compared. Finally, the prospect of Ga2O3-based SBD for power electronics application has been analyzed.
关键词： Breakdown electric field,Baliga’s figure of merit,On-resistance,Ultrawide bandgap semiconductor,Gallium oxide (Ga2O3),Power device,Schottky barrier diode (SBD)
更新于2025-09-23 15:22:29
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Control of Structural and Electrical Properties of Indium Tin Oxide (ITO)/Cu(In,Ga)Se <sub/>2</sub> Interface for Transparent Back-Contact Applications
摘要： Development of transparent-conducting oxide (TCO) back contact for Cu(In,Ga)Se2 (CIGS) absorber is crucial for bifacial CIGS photovoltaics. However, GaOx formation at the TCO/CIGS interface has hampered the photocarrier extraction. Here, by controlling the Na doping scheme, we show that the hole transporting properties at the indium?tin oxide (ITO)/CIGS back contact can be substantially improved, regardless of the GaOx formation. Na incorporation from the glass substrate during the GaOx forming phase created defective states at the interface, which allowed efficient hole extraction from CIGS, while post Na treatment after GaOx formation did not play such a role. Furthermore, we discovered that an almost GaOx-free interface could be made by reducing the underlying ITO film thickness, which revealed that ITO/CIGS junction is inherently Schottky. In the GaOx-free condition, post-Na treatment could eliminate the Schottky barrier and create ohmic junction due to generation of conducting paths at the interface, which is supported by our photoluminescence analysis.
关键词： Schottky barrier,indium-tin oxide,photovoltaics,Na doping,Ga)Se2,ohmic contact,GaOx,transparent-conducting oxide,Cu(In
更新于2025-09-23 15:22:29