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- 实验方案
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Semiconducting Cu-doped AlO<sub>x</sub> films fabricated by drop-photochemical deposition
摘要： Cu-doped aluminum oxides (AlOx) thin films were deposited by the drop photochemical deposition method using an aqueous solution containing Al(NO3)3, Cu(NO3)2 and Na2S2O3. After deposition, the films were annealed at 400oC for 60 min. The Cu-doped AlOx films showed p-type photoresponse in a photoelectrochemical measurement. Moreover, while negligible electrical conductivity was detected for non-doped AlOx on an insulating substrate, electrical conduction was clearly observed for the Cu-doped films with resistivity of the order of 108 Ωcm. The junction between non-doped AlOx and Cu-doped AlOx showed rectification and thus was considered to be a p-n junction. Thus, the conductivity and conduction type of aluminum oxide was controlled by Cu doping.
关键词： p-n junction,photochemical deposition,semiconductor,Cu doping,Aluminum oxide
更新于2025-09-09 09:28:46
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Catechol oxidase mimetic activity of cadmium sulfide nanoparticles for the oxidation of L- 3,4 -dihydroxyphenylalanine
摘要： In the present work we have investigated the oxidation of L-3,4 -dihydroxyphenylalanine (L-Dopa) using colloidal cadmium sulfide nanoparticles (CdS NPs) as a photocatalyst. The CdS NPs were synthesized and characterized using UV-visible absorption spectroscopy, transmission electron microscopy (TEM) and powder X-ray diffraction (XRD). It was demonstrated that the as-prepared CdS NPs mimiced the activity of the catechol oxidase enzyme. To the best of our knowledge, this is the first report on the oxidation of L-Dopa using semiconductor NPs. The kinetic analysis was carried out using the Michaelis-Menten equation. The results observed that the CdS NPs oxidized L-Dopa within 30 min of irradiation using a 200 W Hg(Xe) arc lamp. The oxidation product was identified using high performance liquid chromatography (HPLC). The HPLC analyses were carried out on a reverse-phase C18 column under isocratic conditions using methanol/water (10/90) as the mobile phase. The retention time of the product matched with that of dopachrome. The mechanistic studies indicated the participation of hydroxyl radicals (?OH) in the photocatalytic oxidation of L-Dopa.
关键词： CdS NPs,semiconductor,irradiation,photocatalytic,catechol oxidase
更新于2025-09-09 09:28:46
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[Advances in Intelligent Systems and Computing] Modelling and Simulation in Science, Technology and Engineering Mathematics Volume 749 (Proceedings of the International Conference on Modelling and Simulation (MS-17)) || Computation of Current Density in Double Well Resonant Tunneling Diode Using Self-consistency Technique
摘要： Double well resonant tunneling diode is analytically simulated for different constituent layer widths, and also for different operating temperatures. Peak current densities are obtained at particular bias values, which speak for eigenstates alignment between adjacent quantum wells. Self-consistency technique is incorporated for simulation purpose which provides accurate result regarding the position of the peaks, optimum structural parameters in order to obtain that magnitude, and the junction temperature to obtain measurable current at the applied bias range. It may also be noted that current increases with increase in temperature. Two different dimension set are used for simulation in order to reveal the external influence on electrical properties of the device. Different dimensions of contact regions also help to analyze fluctuations in peak current profile. Thus the device can be operated at those biasing points, where peaks are appeared.
关键词： Resonant tunneling diode,Self-consistency technique,Quantum transport,Current density,Semiconductor heterostructures
更新于2025-09-09 09:28:46
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Photoluminescent and structural properties of color tunable trivalent europium doped SrGdAlO4 nanophosphors
摘要： A series of Eu3+ ion doped SrGdAlO4 nanophosphors were prepared via solution combustion technique utilizing urea as a fuel. Structural properties of the tetragonal phase of the host/doped lattice belonging to the space group I4/mmm were characterized by powder X-ray diffraction (PXRD). Photoluminescence spectra, decay curves, UV–Visible diffuse reflectance spectra (UV–Vis DRS) and Judd–Ofelt analysis were utilized to characterize the photoluminescent properties. The radiative rates (Ar), branching ratios (Br) and intensity parameters (?λ) were estimated by Judd–Ofelt analysis. The optimal doping concentration of europium ions for SrGdAlO4 host lattice was found to be 20 mol%, above which concentration quenching was observed due to dipole–dipole interactions. CIE coordinates values lie in the blue region at lower concentrations of Eu3+ ions, which shifted towards white and then to reddish-orange region with higher concentrations of Eu3+ ions, suggesting the color tunable property of the synthesized nanophosphors. Lower value of CCT and color tunable phenomenon proved it as potential candidate for warm white light and phosphor converted white light emitting diodes (Pc-WLEDs) applications. The optical band gap of both host lattice (5.50 eV) as well as of 20 mol% Eu3+ doped SrGdAlO4 nanophosphors (5.26 eV) lie in the range of semiconductors which enhanced their areas of applications.
关键词： Nanophosphors,Color tunability,Solution combustion,Photoluminescence,Judd–Ofelt analysis,Semiconductor
更新于2025-09-09 09:28:46
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Rare Earth and Transition Metal Doping of Semiconductor Materials || Gadolinium-doped gallium-nitride
摘要： The race toward a dilute magnetic semiconductor (DMS) that exhibits room-temperature (RT) ferromagnetism has been in progress for about 15 years, sparked by the theoretical prediction that the two wide band-gap semiconductors GaN and ZnO would show a Curie temperature (TC) above 300 K if doped with 5% of Mn and a large hole concentration of 1 (cid:1) 1020/cm3 (Dietl et al., 2000). Despite apparent experimental evidence that RT magnetic order was already reported by many groups shortly after the theoretical prediction, the subject remained unusually controversial in the following years. Dietl (2010) summarizes that after 10 years of research the existence of ferromagnetism is well established for GaAs:Mn and related systems but it remains the major goal in the ?eld to achieve TCs at or above 300 K. Around the same time a review of a large group of theorists summarize: “The results of ab initio calculations seem to suggest that it is rather unlikely to obtain TC values as high as room temperature or above in this range” (Sato et al., 2010). Nonetheless persistent experimental claims of TCs above 300 K for a range of DMS materials can be found up to today. Thus it is worth trying to get a broader view on a given materials systems and compare a range of samples from different sources to elucidate whether these reports are characteristic of the DMS material itself (system-speci?c) or if only peculiarities of a given specimen are reported (sample-speci?c). Only in the former case can we consider those ?ndings to be useful for future potential applications in spintronic devices that have to be operational at ambient conditions.
关键词： ferromagnetism,room-temperature,GaN,Gd doping,dilute magnetic semiconductor
更新于2025-09-09 09:28:46
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TE-like mode analysis of microsystem InGaAsP/InP semiconductor resonator generating 20?GHz repetition rate pulse trains
摘要： In microsystem technologies, the microring resonators (MRRs) can be used as a filter device. A wavelength-selective modified add-drop MRR filter is used for adding and dropping a particular wavelength in order to control the light propagation within the system. The spectrum of the mode-locked laser could be generated using a fiber laser loop consisting of active gain medium, EDF, Lumics 980 nm laser diode (LD), wavelength division multiplexer (WDM), isolator, a polarization controller (PC) and carbon nanotube (CNT). The multi-mode-locked laser could be generated at the through and drop port of the system after the mode-locked pulse from the fiber laser circulate within the MRR filter. Here, the mode-locking relies on a fiber laser setup, where the MRR filter has been modeled using the Fimmwave and PICWave softwares. We present this photonic circuits simulator based on the time-domain traveling wave (TDTW) method, provides modeling both active and passive photonic circuits. The pulse bandwidth and repetition of the train mode-locked pulses generated by the fiber laser setup are 0.65 ps and 30 MHz respectively. Using the MRR filter, the drop port output pulses show the FSR and FWHM of 172 pm (20 GHz) and 8.3 pm respectively. The finesse and the Q-factor are approximately 20.72 and 1.9 × 105 respectively.
关键词： InGaAsP/InP semiconductor,TE-like mode,TDTW,Microring resonator (MRR)
更新于2025-09-09 09:28:46
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SiO <sub/>2</sub> etch characteristics and environmental impact of Ar/C <sub/>3</sub> F <sub/>6</sub> O chemistry
摘要： Perfluorocarbon gases are commonly used for nanoscale etching in semiconductor processing; however, they have the disadvantages of a long lifetime and inducing global warming effects when released into the atmosphere. In this study, the SiO2 etch characteristics and global warming effects of C3F6O gas chemistry, which has a low global warming potential, were compared with those of C4F8 chemistry, which is commonly used in semiconductor processing. Using Ar/C3F6O, the SiO2 etch rate was higher and the etch selectivity of SiO2 over the amorphous carbon hardmask layer was lower than the etch rate and etch selectivity using Ar/C4F8/O2, with all other etch conditions the same. Furthermore, using Ar/C3F6O exhibited more anisotropic SiO2 etch profiles by suppressing the bowing, narrowing, and necking effects compared to the etch profiles using Ar/C4F8/O2. The global warming effects were evaluated by calculating the million metric ton carbon equivalents (MMTCEs) from the volumetric concentrations of the emitted by-product species and process gases, and the results showed that, in the optimized conditions, Ar/C3F6O exhibited a lower environmental impact with an MMTCE of <24% than that of Ar/C4F8/O2. Therefore, it is suggested that the Ar/C3F6O gas mixture is a potential replacement for Ar/C4F8/O2 because of its lower MMTCE and acceptable SiO2 etch characteristics.
关键词： C4F8 chemistry,C3F6O gas chemistry,SiO2 etch characteristics,semiconductor processing,global warming effects
更新于2025-09-09 09:28:46
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[IEEE 2018 International Power Electronics Conference (IPEC-Niigata 2018 –ECCE Asia) - Niigata, Japan (2018.5.20-2018.5.24)] 2018 International Power Electronics Conference (IPEC-Niigata 2018 -ECCE Asia) - A Study on Load Fluctuation of Isolated DC-DC Converter with Class Phi-2 Inverter using GaN-HFET
摘要： In recent years, the development and application of GaN-HFET(Heterojunction Field Effect Transistor) has become actively. As GaN-HFETs have advantages in high frequency operation, it is possible to down size power converters by rising switching frequency. In this paper, we investigate the load fluctuation of an isolated DC-DC converter with the class Phi-2 inverter circuit using GaN-HEFT, which is operated at 13.56 MHz.
关键词： DC-DC Converter,Resonant Converter,GaN-HFET,WBG Semiconductor
更新于2025-09-09 09:28:46
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Experimental Characterization of the Influence of Transverse Prestrain on the Piezoresistive Coefficients of Heavily Doped n-Type Silicon
摘要： Strain has been integrated into many silicon devices, as it has an essential impact on carrier mobility and crystal symmetry. Those parameters respond differently under both biaxial and uniaxial, so their effect needs to be quantified to successfully employ the strain engineering in different silicon applications. As an extended step toward utilizing strain in enhancing the sensitivity and the temperature independency of a 3-D stress sensor, the effect of uniaxial transverse strain onto the piezoresistive (PR) coefficients of heavily doped n-type silicon will be experimentally characterized. A new design was developed to apply the transverse tensile and compressive uniaxial stresses onto the silicon substrate using a highly compressive nitride layer. This stressing technique was integrated with six PR elements rosette to fully calibrate the PR coefficients, where unstrained, tensile, and compressive strained PRs are fabricated within the same chip to accurately quantify the strain impact. Four-point bending, stress-free temperature, and hydrostatic test were used to typically measure the PR coefficients. Strain values of 0.065% and 0.083% ε were achieved locally using both the tensile and compressive stressors, respectively. Under this level of strain, the typical result shows opposite impact for both the tensile and compressive transverse strains on the longitudinal and transverse PR coefficients. Moreover, an increase up to 80% can be achieved for the pressure coefficient of heavily doped n-type silicon due to the compressive transverse strain.
关键词： metal–oxide–semiconductor (MOS) local transistors,3-D piezoresistive (PR) sensor,n-type silicon,strain,strain engineering,piezoresistivity
更新于2025-09-09 09:28:46
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Applied Nanophotonics || Electrons in potential wells and in solids
摘要： Absorption and emission of light by atoms, molecules, and solids arise from electron transitions. When in a potential well, an electron has discrete energy spectra; when in a periodic potential it has energy bands separated by gaps. This chapter presents an introductory overview of electron con? nement phenomena and electron properties of crystalline solids. A summary of the data for real semiconductor materials used in photonics is provided.
关键词： electron transitions,photonics,semiconductor materials,energy bands,periodic potential,potential well,energy spectra
更新于2025-09-09 09:28:46