- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Nanoscale Materials in Water Purification || Photocatalysis of Graphene and Carbon Nitride-Based Functional Carbon Quantum Dots
摘要： Day by day, global energy demands increase due to the rapid consumption of depleting fossil fuels and environmental pollution. This has led to the search for materials capable of both energy conversion and elimination of environmental pollutants through the aid of renewable solar energy. This is a promising approach for meeting future energy requirements and eliminating environmental pollutants. In this pursuit, semiconductor photocatalysts have immense potential for solving both energy and environmental issues. To date, numerous semiconductor materials have been explored, including those of metal oxides, chalcogenides, borates, titanates, tungstates, vanadates, zirconates, oxyhalides, and metal-based interstitial compounds. However, the majority of these suffer from limitations such as complex synthesis procedures, limited light absorption range due to their wide band gap, high cost, and toxicity-related issues. Over the past decade, carbon-based nanomaterials have gained attention in the field of photocatalysis. Many recent articles have placed emphasis upon metal-free carbon-based photocatalytic systems for degradation of organic pollutants and hydrogen production from water splitting. The prime merit of these nanomaterials is that they originate from naturally abundant constituent elements such as carbon, nitrogen, and oxygen, making them more economical than their metal-based counterparts. Most reported carbon-based photocatalysts have tunable band gap energies, enhancing their optical absorption range. Band gap energy can be tuned by varying synthesis conditions and precursors, resulting in the formation of nanomaterials with different morphologies. The preparation procedures for most carbon-based nanomaterials are less complex than those of metal-based materials.
关键词： water splitting,energy conversion,semiconductor photocatalysts,graphene,carbon nitride,quantum dots,carbon-based nanomaterials,hydrogen production,solar energy,environmental pollutants,photocatalysis
更新于2025-09-09 09:28:46
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Excitonic effects on layer- and strain-dependent optoelectronic properties of PbI2
摘要： Exciton states have obvious effects on optical properties of two-dimensional (2D) materials. Here, we investigate excitonic effects on electronic and optical properties of PbI2 by using GW + Bethe-Salpeter equation method, considering the layer number and strain effect. These studies show that exciton states obviously modify and dominate the optical absorption of 2D PbI2 nanosheets. Also, with the increasing number of layers, the intensity of main absorption peak increases and the exciton binding energy decreases. Meanwhile, the tensile strain can induce the threshold energy of optical spectra shift down the low energy, and exciton binding energy has a maximum at the strain of 3%. Therefore, our results indicate that the 2D PbI2 nanomaterials have excellent ultraviolet absorption and corresponding potential for the application of optoelectronic devices.
关键词： Optical property,Electronic structure,Lead iodide,Excitonic effects,Two-dimensional semiconductor
更新于2025-09-09 09:28:46
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Band Engineering of Ag-Bi12GeO20-Bi2WO6 Composite Photocatalyst: Interface Regulation and Enhanced Photocatalytic Performance
摘要： Novel Ag-Bi12GeO20-Bi2WO6 heterojunction was developed and demonstrated as an excellent photocatalyst to degrade the Rhodamine B (RhB) aqueous solution with the help of UV-vis light. The Bi12GeO20-Bi2WO6 heterojunction was firstly fabricated through a facile partial chemical conversion strategy, employing pre-prepared Bi2WO6 nanosheets as Bi3+ source. Under the high temperature and high pressure environments, partially released Bi3+ ions derived from the Bi2WO6 nanosheets could react with Ge source, leading to the formation of Bi12GeO20 tetrahedrons. Meanwhile, the remaining Bi2WO6 nanosheets were also anchored in situ onto the surface of the Bi12GeO20 tetrahedrons, thus forming a unique heterojunction with “face-to-face” connection form of heterogeneous interface. After the loading of Ag nanoparticles, the as-obtained Ag-Bi12GeO20-Bi2WO6 heterogeneous structure exhibited outstanding catalytic efficiency toward the decomposition of RhB. Due to the structural and compositional features such as matching band structure, intimate interfacial contacts, unique interface contact structure and the well-known “schottky barriers", the photo-generated charges of the resulting ternary composite photocatalyst was efficiently separated and thus exhibited improved catalytic activity. This rational construction of Ag-Bi12GeO20-Bi2WO6 ternary photocatalytic system based on energy band engineering is ingenious and can provide a mirror for the fabrication of other photocatalytic materials.
关键词： Degradation,Photocatalytic,Band Engineering,Semiconductor
更新于2025-09-09 09:28:46
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Back-Channel-Etched Thin-Film Transistors With Tunable Acid-Resistant Zr-Doped Indium Oxide Active Layer
摘要： In this paper, a tunable acid-resistant Zr-doped indium oxide (ZrInO) semiconductor material was developed. Detailed studies showed that the acid resistance of ZrInO thin films is tunable and increases with the increase in annealing temperature. Taking advantage of this special property, we successfully fabricated back-channel-etched (BCE) thin-film transistors (TFTs) based on the tunable acid-resistant ZrInO thin film. ZrInO-TFTs with BCE structure exhibited excellent electrical performance with a saturation mobility of 21.4 cm2V?1s?1, a subthreshold swing of 0.28 V/decade, and an on/off current ratio of 1.0 × 107. These results envision that the developed ZrInO semiconductor with tunable acid resistance has a good prospect for the channel layer of BCE-TFTs.
关键词： oxide semiconductor,Anodic Al2O3,tunable acid-resistant Zr-doped indium oxide (ZrInO),back-channel etch (BCE),thin-film transistors (TFTs)
更新于2025-09-09 09:28:46
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Gallium Oxide || Low-field and high-field transport in β-Ga2O3
摘要： β-Ga2O3 has recently emerged as a novel wide-bandgap semiconductor with immense potential for applications in power electronics and optoelectronics. Experimental advancements in the past 5 years have been significant toward realizing commercial β-Ga2O3 devices in the near future [1–7]. Matured crystal growth and processing techniques make the material further promising [8–10]. In terms of power electronic applications, MOSFETs based on this material have been demonstrated that could withstand record high voltages [11, 12]. The accuracy of n-type doping and the difficulty of p-type doping make electrons the primary charge carriers in β-Ga2O3. Although β-Ga2O3 has lower electron mobility compared to other wide-bandgap semiconductors, it is found to have a superior Baliga’s figure of merit that jointly accounts for on-state resistance and breakdown voltage [4]. So it is important to investigate in rigor the fundamentals behind β-Ga2O3 material properties that could be beneficial to gain an understanding on the causes that control mobility and breakdown voltage. There are theoretical reports on fundamental materials aspects including electronic structure [13] and optical properties [14], lattice dynamical and dielectric properties [15], and thermal properties [16, 17] as well. The primary physics behind both mobility (and hence the device on resistance) and breakdown voltage lies in the electron transport phenomenon. There have been a few experimental reports that try to characterize the electron transport and scattering mechanisms in β-Ga2O3 with Hall measurements being reported a few times to predict temperature dependence and also crystal orientation dependence of the electron mobility [18, 19]. On the other hand, we are making a systemic study on the theoretical understanding of electron transport in β-Ga2O3 starting from the first principles [20–22]. The main idea is to follow a bottom-up approach in order to develop an understanding of the near-equilibrium and far-from-equilibrium electron dynamics in β-Ga2O3. This is unique compared to conventional semiconductors in a way that β-Ga2O3 has a low-symmetry crystal structure and a fairly large primitive unit cell that gives rise to many phonon modes. On several occasions, the traditional notions of electron transport that are applicable to Si and GaAs actually do not quite hold well in the case of β-Ga2O3. In this chapter, we attempt to provide a comprehensive picture of electron transport in β-Ga2O3 under low and moderately high electric fields based on our work in the recent years.
关键词： electron-phonon interaction,β-Ga2O3,electron mobility,power electronics,optoelectronics,electron transport,velocity-field curves,wide-bandgap semiconductor
更新于2025-09-09 09:28:46
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Dependence of Short-Channel Effects on Semiconductor Bandgap in Tunnel Field-Effect Transistors
摘要： Scaling down the bandgap is considered as an essential approach to enhance the performance of tunnel field-effect transistors (TFETs). Using two-dimensional simulations, this study examines the dependence of short-channel effects on the semiconductor bandgap in TFETs. It is shown that the short-channel effect is more severe with using lower bandgap materials although the supply voltage is scaled in parallel with the bandgap. For a given bandgap material, the short-channel effect can be well evaluated by the increase of drain-induced barrier thinning (DIBT) with decreasing the channel length. For different bandgap TFETs, however, their short-channel effects cannot be compared properly by comparing the DIBTs. Adequately considering the effect of bandgap on the TFET scalability is necessary in designing scaled integrated circuits.
关键词： drain-induced barrier thinning,tunnel field-effect transistors,DIBT,semiconductor bandgap,TFETs,short-channel effects
更新于2025-09-09 09:28:46
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Gallium Oxide || Ohmic contacts to gallium oxide
摘要： The deposition of a metal onto a semiconductor surface to provide low contact resistance, high-reliability electrical contacts without adversely affecting the device during the metallization process is one of the most important challenges in device fabrication. Consequently, a fundamental understanding of how contacts work is essential for successful device manufacturing and commercialization. The physics of carrier transport across the metal-semiconductor junction renders metal contacts either rectifying (a.k.a. Schottky) or nonrectifying. A nonrectifying contact whose relationship between current and voltage has a low interfacial contact resistance Rc, and is preferably linear, is referred to as an Ohmic contact. Achieving low contact resistance Rc (Ω mm) or contact resistivity ρc (Ω cm2) has required a great amount of investigation for every relevant semiconductor material in the past. Typically, the successful formation of an Ohmic contact has relied on three constituent requirements: highly or degenerately doped semiconductor, choice of metallization, and thermal annealing. In the case of silicon, for instance, diffusion processes have been the topic of much early work but ultimately the control and reproducibility of ion implantation have rendered it an industry standard. For compound semiconductor heterostructure devices based on GaAs or GaN, the presence of a two-dimensional electron gas (2DEG) has necessitated a multilayer metallization deposition and annealing scheme, the details of which took many years to optimize. Particularly in the case of III-nitride high electron mobility transistors (HEMTs), Ohmic contacts were relatively easy to make on heteroepitaxal GaN due to its high dislocation density as the barrier height was reduced through defect-assisted formation of metal-nitride alloys during the anneal. Subsequent breakthroughs in GaN crystal growth, however, resulted in several orders of magnitude lower dislocation density homoepitaxial GaN, and naturally the contact resistance obtained under identical process conditions was higher [1]. Regrowth techniques to provide n+-doped GaN have become commonplace as a result.
关键词： thermal annealing,semiconductor,metallization,gallium oxide,contact resistance,Ohmic contacts
更新于2025-09-09 09:28:46
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with pentagonal structure
摘要： Structure-property relationships have always been guiding principles for materials discovery. Here we explore the relationships to discover two-dimensional (2D) materials with the goal of identifying 2D magnetic semiconductors for spintronics applications. In particular, we report a density functional theory + U study of single-layer antiferromagnetic (AFM) semiconductor CoS2 with the pentagonal structure forming the so-called Cairo tessellation. We ?nd that this single-layer magnet exhibits an indirect band gap of 1.06 eV with electron and hole effective masses of 0.52 and 1.93 m0, respectively, which may lead to relatively high electron mobility. The hybrid density functional theory calculations correct the band gap to 2.24 eV. We also compute the magnetocrystalline anisotropy energy (MAE), showing that the easy axis of the AFM ordering is along the b axis with a sizable MAE of 153 μeV per Co ion. We further calculate the magnon frequencies at different spin-spiral vectors, based on which we estimate the N′eel temperatures to be 20.4 and 13.3 K using the mean ?eld and random phase approximations, respectively. We then apply biaxial strains to tune the band gap of single-layer pentagonal CoS2. We ?nd that the energy difference between the ferromagnetic and AFM structures strongly depends on the biaxial strain, but the ground state remains the AFM ordering. Although the low critical temperature prohibits the magnetic applications of single-layer pentagonal CoS2 at room temperature, the excellent electrical properties may ?nd single-layer semiconductor applications in optoelectronic nanodevices.
关键词： two-dimensional materials,magnon frequencies,N′eel temperature,biaxial strain,Cairo tessellation,antiferromagnetic semiconductor,density functional theory,band gap,magnetocrystalline anisotropy energy,pentagonal structure,spintronics
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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Effects of Te additions and stirring in the In segregation in Ga1-xInxSb alloys
摘要： The influence of tellurium in the indium segregation of Ga1-xInxSb:Te ingots obtained by the conventional vertical Bridgman method (CVBM), under stirred and non-stirred conditions, was investigated. Three Te-doped ingots and three no-doped ingots were unidirectionally solidified at a constant speed of 2.0 mm/hour, inside quartz ampoules, closed under argon, and with a conical tip. The furnace temperature was set for overheating between 73.5 – 93°C, and temperature gradients between 3.0 – 3.3°C/mm. The tellurium doped ingots showed a smaller number of grains and no cracks in the middle region of the ingots, right after the tip, in comparison with the no-doped ingots. Moreover, when comparing the stirred with the non-stirred ingots, the EDS experimental profile of indium in Te-doped synthetized without melt stirring ingot showed a better agreement with the Scheil–Gulliver equation than the stirred Te-doped ingots. The Te-doped ingots when stirring the melt during synthesis showed a more constant axial indium distribution, up to 85% of their lengths. The constant lattice estimated from TEM diffraction images are respectively 6.29 ? for the non-doped sample and 6.17 ? for the Te-doped sample. A qualitative account for the increase of the lattice parameter and the Hall measurements results is that the tellurium compensates for the native acceptor defects, contributing to the microstructural quality in the Ga1-xInxSb ingots.
关键词： vertical Bridgman,GaInSb,compound semiconductor III-V,tellurium,bulk crystals
更新于2025-09-09 09:28:46