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Difluorophosphorane - Flattened Phosphorene through Difluorination
摘要： We computationally showed that by difluorination of phosphorene we can make a new material difluorphosphorane (DFP) with perfectly planar honeycomb structure out of phosphorus atoms with fluorine atoms attached to every phosphorus atom from above and below. The structure is dynamically stable. It is a semiconductor with the direct band gap of 4.51 eV and 3.88 eV for the indirect band gap. We hope that with the passivation this new DFP material if made could find many applications in nanoelectronics.
关键词： difluorination,difluorophosphorane,nanoelectronics,phosphorene,semiconductor
更新于2025-09-23 15:21:21
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Semiconducting Langmuir-Blodgett Films of Porphyrin Paddle-Wheel Frameworks for Photoelectric Conversion
摘要： Understanding the photocurrent transportation within porphyrin-containing metal-organic frameworks (PMOFs) will be a critical step for applying these materials in light-harvesting molecular devices in the future. Two copper porphyrin paddle-wheel frameworks (Cu-PPFs) were employed to study the influence of metal ions coordinated into the porphyrin ligands on conductivity and photoelectron transfer capability. To compare the electronic and optical properties of both materials, we prepared an ultra-thin film of each PPF via a Langmuir-Blodgett method. The resulting films exhibited uniform morphology and single-crystalline domains, in addition to photoelectric conversion capabilities. We confirmed both Cu-PPFs have semiconducting properties with an optical bandgap around 2.7 eV. The current density generated by both Cu-PPFs were studied through a mercury drop junction approach. We observed a slightly higher conductivity from the Cu-PPF film consisting of metalloporphyrins than the one without copper doping in the porphyrin centers. In addition, the copper ions coordinated porphyrins were found to be more favorable for facilitating photo-induced electron transfer from the Cu-PPF film to a conductive glass substrate. This work presents a new approach of combining thin film fabrication and electro-heterojunction measurement to study electron transfer within an ultra-thin film.
关键词： Metal-Organic Framework (MOF),2D Material,Langmuir-Blodgett Film,Self-Assembly,Semiconductor,Porphyrin Thin Film,Photoelectric Conversion
更新于2025-09-23 15:21:21
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Handbook of Ecomaterials || Environmental Photocatalysis/Photocatalytic Decontamination
摘要： Water pollution caused by hazardous substances has become a global concern. Textile and dyestuff industries produce large amounts of wastewater containing various dye pollutants. Most azo dyes are nonbiodegradable and their release into the environment poses a major threat to the surrounding ecosystems. Remediation of organic aquatic pollutants by photocatalytic oxidation has proven to be an attractive promising technology among the advanced oxidation processes. Semiconductor photocatalysis is a topic of current interest mainly in view of its potential application in the mineralization of pollutants.
关键词： Pilot scale treatment,Heterogeneous photocatalysis,Air purification,Antimicrobial activity,Semiconductor oxides,Water pollution
更新于2025-09-23 15:21:21
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Electronic transport in degenerate (100) scandium nitride thin films on magnesium oxide substrates
摘要： Scandium nitride (ScN) is a degenerate n-type semiconductor with very high carrier concentrations, low resistivity, and carrier mobilities comparable to those of transparent conducting oxides such as zinc oxide. Because of its small lattice mismatch to gallium nitride (GaN), <1%, ScN is considered a very promising material for future GaN based electronics. Impurities are the source of the degeneracy. Yet, which specific impurities are the cause has remained in contention. ScN thin films of various thicknesses were grown on magnesium oxide substrates in a (001) orientation using reactive magnetron sputtering across a range of deposition conditions. X-ray diffraction was used to verify crystal orientation. Film thicknesses ranging from 39 to 85 nm were measured using scanning electron microscopy. The electronic transport properties of the films were characterized using Hall-effect measurements at temperatures ranging from 10 to 320 K. At 10 K, the electron concentration varies from 4.4 (cid:2) 1020 to 1.5 (cid:2) 1021 cm(cid:3)3, resistivity from 2.1 (cid:2) 10(cid:3)4 to 5.0 (cid:2) 10(cid:3)5 X(cid:4)cm, and Hall mobility from 66 to 97 cm2/V(cid:4)s. Secondary ion mass spectroscopy (SIMS) was used to determine film compositions. Finally, density functional theory (DFT) was used to compute the activation energies for various point defects including nitrogen and scandium vacancies and oxygen and fluorine substituting for nitrogen. For both oxygen and fluorine substitution, the energies were negative, indicating spontaneous formation. Nevertheless, the combined results of the Hall, SIMS, and DFT strongly suggest that oxygen substitution is the primary mechanism behind the high carrier concentration in these samples.
关键词： degenerate n-type semiconductor,Hall-effect measurements,Scandium nitride,density functional theory,electronic transport properties
更新于2025-09-23 15:21:21
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The optical response of self-organized Ag-CdTe metal-semiconductor hybrid nanostructures: Change in interaction vs number density variation
摘要： Using experimental results and a theoretical model, we establish a relation for the optical response of a mixed nanocolloid. We show that colloids prepared by mixing metal and semiconductor nanocolloids in various ratios result in a mixture composed of a particular metal-semiconductor hybrid nanostructure and unattached original particles. Thus, the properties of hybrid samples prepared by such self-organized growth are decided by the variation in number density of the hybrid and the unattached particles and not due to a continuous change in the interaction between metal nanoparticles and semiconductor quantum dots as was assumed earlier. Using these results, a method to prepare a single type of hybrid nanostructure by measuring only its optical response is presented.
关键词： nanoparticles,metal-semiconductor hybrid nanostructures,optical response,quantum dots,self-organized growth
更新于2025-09-23 15:21:21
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Room temperature spin injection into SiC via Schottky barrier
摘要： Electrical spin injection into and spin extraction from a wide-bandgap semiconductor SiC at room temperature were demonstrated via Schottky junctions. The spin relaxation time of SiC could reach 300 ps, overwhelming that of Si with similar carrier density due to the smaller atomic number. We also found that there existed two channels in SiC/CoFeB Schottky junctions for spin relaxation, one from bulk SiC and the other from interfacial defect states within the barrier whose spin relaxation times were about 1 ns. The bias condition controlled transport channels via bulk or defect states within the barrier and then affected the effective spin relaxation process. Realization of spin injection into SiC shed light on spintronics of wide-bandgap semiconductors such as spin-resolved blue light emitting diodes and high power/temperature spintronics.
关键词： spintronics,SiC,spin injection,Schottky barrier,wide-bandgap semiconductor
更新于2025-09-23 15:21:21
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Chemical use in the semiconductor manufacturing industry
摘要： Background: The semiconductor industry is known to use a number of chemicals, but little is known about the exact chemicals used due to the ingredients being kept as a trade secret. Objectives: The objective of this study was to analyze chemical use using a safety data sheet (SDS) and chemical inventory provided by a major semiconductor company, which operated two factories (A and B). Methods: Descriptive statistics were obtained on the number of chemical products and ingredients, photoresists, and carcinogens, classified by the International Agency for Research on Cancer (IARC), as well as trade secret ingredients. The total chemical use per year was estimated from chemical inventories mass (kg). Results: A total of 428 and 432 chemical products were used in factories A and B, respectively. The number of pure chemical ingredients, after removing both trade secret ingredients and multiple counting, was 189 and 157 in factories A and B, respectively. The number of products containing carcinogens, such as sulfuric acid, catechol, and naphthalene was 47/428 (A) and 28/432 (B). Chemicals used in photolithography were 21% (A) and 26% (B) of all chemical products, and more than 97% among them were chemicals containing trade secret ingredients. Conclusions: Each year, 4.3 and 8.3 tons of chemicals were used per person in factories A and B, respectively. Because of the high level of commercial secrecy and the use of many unregulated chemicals, more sustainable policies and methods should be implemented to address health and safety issues in the semiconductor industry.
关键词： SDS,trade secret ingredients,chemical,Semiconductor,photolithography
更新于2025-09-23 15:21:21
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[IEEE 2020 12th International Conference on Measuring Technology and Mechatronics Automation (ICMTMA) - Phuket, Thailand (2020.2.28-2020.2.29)] 2020 12th International Conference on Measuring Technology and Mechatronics Automation (ICMTMA) - Review on PD Ultrasonic Detection Using EFPI - Part I: the Optical Fiber Sensing Technologies
摘要： We report the development of multistrata subsurface laser-modified microstructure with backgrind-assisted controlled fracture for defect-free ultrathin die fabrication. This study focuses on the microstructural properties and formation mechanisms of the subsurface Si dislocation belt layer with respect to laser scanning speed, pulse laser energies, and interstrata distances. We optimize and exploit the multistrata interactions between generated thermal shock waves and the preceding dislocation belt layers formed to initiate frontal crack fractures that separate out the individual dies from within the interior of the wafer. A new partial-SD before grinding (p-SDBG) integration scheme based upon the tandem use of three-strata SD for controlled crack fracture toward the frontside of the wafer followed by static loading from backgrinding to complete full kerf separation is demonstrated. The optimized three-strata SD process and p-SDBG integration scheme can be used to compensate for the high backside reflectance wafers to produce defect-free eight die stacks of 25-μm-thick mechanically and 46-μm-thick electrically functional 2-D NAND memory dies.
关键词： laser,semiconductor device packaging,semiconductor memory,Defects,wafer dicing,semiconductor device manufacture
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Toward >25% Efficient Monolithic Epitaxial GaAsP/Si Tandem Solar Cells
摘要： We report here on progress made in the development of >20% efficient monolithic epitaxial III-V/Si tandem solar cells. Following our prior demonstration of a GaAs0.75P0.25/Si tandem cell with verified AM1.5G efficiency of 20.1%, we have undertaken intensive efforts aimed at optimization of the top and bottom subcells, involving both materials quality improvement and detailed device structure refinement. To date we have thus demonstrated 21.8% AM1.5G GaAs0.75P0.25/Si tandem cells making use of an optimized, but still defect-limited GaAsP top cell combined with a simple diffusion-processed (emitter and back-surface field) Si bottom cell. With recent development of a low dislocation density III-V-on-Si epitaxial materials platform, as well as bottom cell enhancements for photon management, analytical performance loss analysis and efficiency projections indicate that >25% is achievable in the near-term, and 30% within reach with additional holistic optimization.
关键词： photovoltaic cells,Si,III-V semiconductor materials,semiconductor epitaxial layers
更新于2025-09-23 15:21:01
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Vertically coupled InP/InGaAsP microring lasers using a single epitaxial growth and single-side lithography
摘要： The experimental demonstration of vertical microring lasers requiring only one single epitaxial growth and two single-side lithographic steps is presented, in what is the simplest fabrication scheme for such devices published to date. The fabricated lasers show series resistance of around 20 Ω at forward bias, threshold currents at room temperature between 35 and 58 mA, and single-mode emission with a side-lobe suppression ratio higher than 30 dB. The measured optic output power level is of tens of microwatts. The approach allows the improvement of the optical features maintaining the simplicity of the manufacturing procedure.
关键词： semiconductor lasers,semiconductor waveguides,Integrated optics,ring lasers
更新于2025-09-23 15:21:01