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Structure of AlN on Si (111) Deposited with Metal Organic Vapor Phase Epitaxy

MRS Internet Journal of Nitride Semiconductor Research 2020年第1期4卷 322-326页

作者： Rehder, Eric Zhou, M. Zhang, L. Perkins, N. R. Babcock, S. E. Kuech, T. F. Materials Science Program University of Wisconsin -Madison Madison USA Dept. of Materials Science University of Wisconsin -Madison Madison USA Dept. of Chemical Engineering University of Wisconsin -Madison Madison USA

The surface morphology and structure of AlN deposited by metal organic vapor phase epitaxy (MOVPE) on Si (111) at growth temperatures ranging from 825 to 1175°C was investigated. Transmission electron microscopy (TEM), reflection high energy electron diffraction (RHEED), atomic force microscopy (AFM), and secondary ion mass spectrometry (SIMS) techniques were used to study the resulting film structure. Growth at high temperatures but less than ∼1100°C, resulted in a wire texture with some degree of in-plane alignment with (0001)AlN/ /(111)Si, < 10 $$\bar 1$$ 0>AlN//< $$\bar 2$$ 11>Si, and 11 $$\bar 2$$ 0>AlN//< $$\bar 1$$ 10>Si. Deposition at temperatures greater than 1100°C results in single crystal films consisting of domains 60 nm across with an aspect ratio near unity. Growth below1100°C leads to degraded crystal quality with the grains developing random rotational misalignments around the AlN [0001] axis. Growth at lower temperatures produces islands elongated along the [11 $$\bar 2$$ 0] direction. At the growth temperature of 825°C, the aspect ratio of the islands increased to 3 and a width of 25 nm. Cross-sectional TEM reveals that these islands are faceted due to slow growth on the {1 $$\bar 1$$ 01}planes.

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Extruded LZS glass-ceramics

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American Ceramic Society Bulletin 2004年第8期83卷

作者： Montedo, O.R.K. Reitz, G.M. Bertan, F.M. De Novaes Oliveira, A.P. Hotza, D. Siligardi, C. Graduate Program in Materials Science and Engineering Federal University of Santa Catarina Florianópolis Brazil Dept. of Materials and Environment Engineering University of Modena and Reggio Emilia Modena Italy

Experimental results regarding Li2O-ZrO2-SiO 2 (LZS) sintered glass ceramic materials obtained by extrusion of glass powders with an added inorganic material as binder, are presented. Each of the composition were characterized by chemical analysis, laser scattering particle-size analysis, differential thermal analysis (DTA), Xray diffractometry (XRD), and thermal expansion. It was observed that after a sintering process at near by 750°C, crystallization takes place as soon as the process gets over. Once heated, the the glass powder compacts crystallize into zircon and quartz and then to lithium disilicate.

关键词： Glass ceramics

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Nanothick layer transfer of hydrogen-implanted wafer using polysilicon sacrificial layer

Nanothick layer transfer of hydrogen-implanted wafer using p...

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2006 MRS Spring Meeting

作者： Huang, C.H. Chang, C.L. Yang, Y.Y. Suryasindhu, T. Liao, W.-C. Su, Y.-H. Li, P.W. Liu, C.-Y. Lai, C.S. Ting, J.-H. Chu, C.S. Lee, C.-S. Lee, T.-H. Dept. of Mechanical Engineering National Central University Chung-Li Taiwan Dept. of Electrical Engineering National Central University Chung-Li Taiwan Dept. of Chemical and Materials Engineering National Central University Chung-Li Taiwan Department and Graduate Institute of Electrical Engineering Chang Gung University Kwei-Shan Taiwan National Nano Device Laboratories Hsinchu Taiwan United SOI Corporation Berkeley CA 94707 United States Dept. of Physics National Central University Chungli 320 Taiwan Inst. of Materials Science and Engineering National Central University Chung-Li Taiwan

ISBN: (纸本)1558998780

A fabrication method of 2-D nanostructure materials applied for forming nanothick SOI materials without using post-thinning processes is presented in this paper. The thickness of SOI layer is precisely controlled by a polysilicon layer as a sacrificial layer in the implantation step to acquire a desirable implant dept.. Polysilicon layer was initially deposited on the thermal oxidized surface of silicon wafer prior to the ion implantation step with 4×1016 /cm-2,160KeV, H2+ ions. The as-implanted wafer was contained a hydrogen-rich buried layer which dept. from the top surface is less than 100 nm. Before this as-implanted wafer being bonded with a handle wafer, the polysilicon layer was removed by a wet etching method. A nanothick silicon layer was then successfully transferred onto a handle wafer under 10-minute microwave irradiation after the bonding step. The thickness of the final transferred silicon layer was 100 nm measured by transmission electron microscopy (TEM). © 2006 materials Research Society.

关键词： Silicon on insulator technology

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Nucleation and Growth of Gallium Nitride Films on Si and Sapphire Substrates Using Buffer Layers

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MRS Online Proceedings Library 2011年第1期423卷 287-292页

作者： N.R. Perkins M.N. Horton D. Zhi R.J. Matyi Z.Z. Bandic T.C. McGill T.F. Kuech Materials Science Program University of Wisconsin Madison USA Department of Materials Science and Engineering University of Wisconsin Madison USA Department of Applied Physics California Institute of Technology Pasadena USA Dept. of Chemical Engineering University of Wisconsin Madison USA

We have investigated the nucleation and growth of gallium nitride (GaN) films on silicon and sapphire substrates using halide vapor phase epitaxy (HVPE). GaN growth was carried out on bare Si and sapphire surfaces, as well as on MOVPE-grown GaN buffer layers. HVPE growth on MOVPE GaN/AIN buffer layers results in lower defect densities as determined by x-ray than growth directly on sapphire. HVPE GaN films grown directly on sapphire exhibit strong near-edge photoluminescence, a pronounced lack of deep level-based luminescence, and x-ray FWHM values of 16 arcsec by an x-ray θ-2θ scan. The crystallinity of GaN films on sapphire is dominated by the presence of rotational misorientation domains, as measured by x-ray ω-scan diffractometry, which tend to decrease with increasing thickness or with the use of a homoepitaxial MOVPE buffer layer. The effect of increasing film thickness on the defect density of the epilayer was studied. In contrast, the HVPE growth of nitride films directly on silicon is complicated by mechanisms involving the formation of silicon nitrides and oxides at the initial growth front.

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Halide Vapor Phase Epitaxy of Gallium Nitride Films on Sapphire and Silicon Substrates

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MRS Online Proceedings Library 2011年第1期395卷 243-248页

作者： N.R. Perkins M.N. Horton Z.Z. Bandic T.C. McGill T.F. Kuech University of Wisconsin Materials Science Program Madison USA Department of Applied Physics California Institute of Technology Pasadena USA Dept. of Chemical Engineering University of Wisconsin Madison USA

A major limitation of the current technology for GaN epitaxy is the availability of suitable substrates matched in both lattice constant and thermal expansion coefficient. One alternative for the development of GaN substrates rests in the application of halide vapor phase epitaxy (HVPE) to produce GaN films at high growth rates. In this paper, we describe the growth of thick GaN films via the HVPE technique on (0001) sapphire and (111) Si substrates. At a temperature of 1030°C, films are grown at rates between 70 and 90 μm/hr, yielding total thicknesses exceeding 200 μm on sapphire. DCXRD measurements of GaN/sapphire indicate FWHM values less than 220 arcsec on 180 μm thick films. Room temperature PL measurements of GaN/sapphire indicate strong emission at 3.41 eV, with a FWHM value of 65 meV. Moreover, no detectable deep level emission was found in room temperature PL measurement. Under optimized conditions, films are morphologically smooth and optically clear. The GaN morphology appears to be a strong function of the initial nucleation conditions, which in turn are strongly affected by the partial pressure of GaCl. HVPE growth on (111) Si substrates is accomplished using an AlN MOVPE buffer layer.

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Spectrophotometer on a focal-plane-array chip for the high-throughput analysis of enzymatic reaction

Spectrophotometer on a focal-plane-array chip for the high-t...

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2003 IEEE LEOS Annual Meeting Conference Proceedings

作者： Wang, Dong Ha, Chanki Park, Chan Beum Joo, Youngjoong Department of Electrical Engineering Arizona State University Tempe AZ United States Science and Eng. of Mat. Program Arizona State University Tempe AZ United States Dept. of Chemical and Materials Eng. Arizona State University Tempe AZ United States

An on-chip spectrophotometer system, consisting of a CMOS focal-plane-array and polydimethylsiloxane (PDMS) microfluidic flow channels, is described. One of the potential applications of this prototype system is to pe... 详细信息

关键词： Spectrophotometers

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Investigating long term storage stability and drug release behavior of polypeptide based fibrous scaffold for tissue engineering application

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materials Chemistry and Physics 2024年 321卷

作者： Chang, Chun-Yu Su, An-Jey A. Lin, Meng-Fang Hsiao, Kai-Chi Lee, Chia-Hsien Lin, Yu-Ting Hsiao, Yu-Sheng Wu, Ming-Chung Huang, Yu-Ching Su, Wei-Fang Bachelor Program in Semiconductor Materials and Fabrication Ming Chi University of Technology Taiwan Dept. of Surgery Anschutz Medical Campus University of Colorado AuroraCO United States Dept. of Materials Engineering Ming Chi University of Technology Taiwan Dept. of Chemical and Materials Engineering Chang Gung University Taiwan Dept. of Materials Science and Engineering National Taiwan University of Science and Technology Taipei City Taiwan Dept. of Materials Science and Engineering National Taiwan University Taiwan

Electrospun poly (γ-benzyl-L-glutamate) (PBG) scaffold felt with aligned fibers shows promising nerve regeneration and neurite growth capability due to the nerve stimulating moiety of glutamate in the PBG material. The nerve regeneration capability can be further enhanced by incorporating 4 wt% minocycline hydrochloride (MH) in the scaffold (PBGMH4). They are useful in the nerve tissue engineering to repair and regeneration damaged nerves in central nerve system or peripheral nerve system. Here we investigate the ambient storage capability of PBG and PBGMH4 by monitoring the changes over time of fiber dimension, mechanical properties of both scaffolds and amount of drug release of PBGMH4. It is interesting to observe the diameter of fibers and mechanical strength of scaffolds increases but the amount of drug release decrease with time. By carefully examining the top view of the scaffolds using scanning electron microscopy (SEM), the fiber diameter of PBG increased by 58 % over the 12 months storage period, which is larger than the 32 % increase observed for PBGMH4. Furthermore, after storage for 12 months, the difference in fiber diameter between the top and bottom sides of PBG scaffold is 25.9 %, whereas for PBGMH4 is only 6.3 %. These results demonstrate that the PBGMH4 scaffold exhibits superior storage stability compared to that of PBG. Because the fibers of the scaffolds are aligned without any crosslinkage, the scaffolds are porous structure of felts. The porosity of PBGMH4 scaffold is decreased from 90 % to 72 % which can be accountable for the decrease of drug release from initial 42 % to a stabilized 26 % after 9 months of storage. The results indicate the specific surface area of the scaffolds play an important role in governing drug release kinetics. This study thoroughly investigates the storage stability of PBG and PBGMH4 electrospun fibrous scaffolds. The observed correlations between fiber diameter, mechanical properties, and drug release behavior hol

关键词： Electrospinning

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Investigating Long Term Storage Stability and Drug Release Behavior of Polypeptide Based Fibrous Scaffold for Tissue engineering Application

SSRN

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SSRN 2024年

作者： Chang, Chun-Yu Su, An-Jey Lin, Meng-Fang Hsiao, Kai-Chi Lee, Chia-Hsien Lin, Yu-Ting Hsiao, Yu-Sheng Wu, Ming-Chung Huang, Yu-Ching Su, Wei-Fang Bachelor Program in Semiconductor Materials and Fabrication Ming Chi University of Technology Taiwan Dept. of Surgery Anschutz Medical Campus University of Colorado AuroraCO United States Dept. of Materials Engineering Ming Chi University of Technology Taiwan Dept. of Chemical and Materials Engineering Chang Gung University Taiwan Dept. of Materials Science and Engineering National Taiwan University of Science and Technology Taipei City Taiwan Dept. of Materials Science and Engineering National Taiwan University Taiwan

Electrospun poly (γ-benzyl-L-glutamate) (PBG) scaffold felt with aligned fibers shows promising nerve regeneration and neurite growth capability due to the nerve stimulating moiety of glutamate in the PBG material. The nerve regeneration capability can be further enhanced by incorporating minocycline hydrochloride drug in the scaffold (PBGMH). They are useful in the nerve tissue engineering to repair and regeneration damaged nerves in central nerve system or peripheral nerve system. Here we investigate the ambient storage capability of PBG and PBGMH by monitoring the changes over time of fiber dimension, mechanical properties of both scaffolds and amount of drug release of PBGMH. It is interesting to observe the diameter of fibers and mechanical strength of scaffolds increases but the amount of drug release decrease with time. By carefully examine the top view and bottom view of the 40 micron thick scaffolds by scanning electron microscopy (SEM), the increased diameter of fibers on the top of the scaffold is less than that of the bottom of the fiber. Because the fibers of the scaffold are aligned without any crosslinkage, it is a porous structure of felt, the fibers of scaffolds are settled down with gravity. The porosity of PBG scaffold is decreased from 90% to 72% which can be accountable for the decrease of drug release from initial 42% to a stabilized 26% after nine months of storage. The results indicate the specific surface area of the scaffold play an important role in governing drug release kinetics. This study thoroughly investigates the storage stability of PBG electrospun fibrous scaffold. The observed correlations between fiber diameter, mechanical properties, and drug release behavior hold implications for the design of advanced bioscaffolds. The long shelf life of optimal PBGMH4 scaffold shows potential application for the nerve regeneration and controlled drug delivery systems. © 2024, The Authors. All rights reserved.

关键词： Fibers

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Silica-supported Cu Complex Catalysis for Chan–Evans–Lam Coupling Reaction between Aniline and Phenylboronic Acid

Silica-supported Cu Complex Catalysis for Chan–Evans–Lam C...

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作者： Motokura, Ken Gomi, Kyosuke Maeda, Kyogo Sakai, Shunichi Hasegawa, Shingo Chun, Wang-Jae Manaka, Yuichi Dept. of Chemistry and Life Science Yokohama National University 79-5 Tokiwadai Hodogaya-ku Yokohama240-8501 Japan Dept. of Chemical Science and Engineering School of Materials and Chemical Technology Tokyo Institute of Technology 4259 Nagatsuta-cho Midori-ku Yokohama226-8502 Japan Graduate School of Arts and Sciences International Christian University 3-10-2 Osawa Mitaka Tokyo181-8585 Japan 2-2-9 Machiikedai Fukushima Koriyama963-0298 Japan

Silica-supported Cu(II) acetate complexes were prepared and characterized via elemental analysis and several spectroscopic techniques. Cu K-edge X-ray absorption fine structure (XAFS) analysis revealed the presence of a Cu(II) complex with a diamine ligand. The catalyst with a co-immobilized tertiary amine showed a higher performance for the Chan-Evans-Lam coupling reaction of aniline with phenylboronic acid to produce diphenylamine compared with the catalyst without a tertiary amine. Characterization and catalytic reaction results indicated that the tertiary amine accelerates transmetallation between the Cu(II) complex and phenylboronic acid, producing Cu-Ph species. © 2023 Japan Petroleum Institute. All rights reserved.

关键词： Aniline

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Enhancing mechanical properties of graphene / epoxy nanocomposites using few-layer graphene produced by liquid phase exfoliation 18

Enhancing mechanical properties of graphene / epoxy nanocomp...

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18th European Conference on Composite materials, ECCM 2018

作者： Oba, K. Arao, Y. Hosoi, A. Kawada, H. Dept. of Applied Mechanics Graduate School of Waseda University 3-4-1 Okubo Shinjuku Tokyo169-8555 Japan Dept. of Chemical Science and Engineering Tokyo Institute of Technology 2-12-1 O-okayama Meguro Tokyo152-8550 Japan Dept. of Applied Mechanics and Aerospace Engineering Waseda University 3-4-1 Okubo Shinjuku Tokyo169-8555 Japan Kagami Memorial Research Institute for Materials Science and Technology Waseda University 2-8-16 Nishi-Waseda Shinjuku Tokyo169-0051 Japan

ISBN: (纸本)9781510896932

In this study, few-layer graphenes (FLGs) were produced by new liquid phase exfoliation (LPE), exfoliation of graphite with weak acid salts. A high concentration dispersion of FLGs in low-boiling point solvents is successfully carried out, achieved by binding molecules with a dispersing function. And then graphene/epoxy nanocomposites were fabricated and tensile properties were evaluated in order to understand the effect of FLGs introduced into the resin. Graphene/epoxy nanocomposite showed improved mechanical properties. Tensile strength and fracture strain were increased by 11.5% and 55.6% compared with as-received one's. Especially, the improvement of fracture strain was outstanding, which indicated that adding FLGs had a positive impact on suppressing effect on crack propagation and improving fracture toughness of matrix resin. These beneficial results were derived from crack trapping by uniformly dispersed FLGs. © CCM 2020 - 18th European Conference on Composite materials. All rights reserved.

关键词： Graphene

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