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Optical properties in 1D photonic crystal structure using si/C_(60) multilayers

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Journal of Semiconductors 2009年第4期30卷 7-9页

作者：谌静唐吉玉韩培德陈俊芳 College of Physics and Telecommunication Engineering South China Normal University College of Materials Science and Engineering Taiyuan University of Technology

The feasibility of using si/C60 multilayer films as one-dimensional （1D） photonic band gap crystals was investigated by theoretical calculations using a transfer matrix method （TMM）. The response has been studied both within and out of the periodic plane of si/C60 multilayers. It is found that si/C60 multilayer films show incomplete photonic band gap （PBG） behavior in the visible frequency range. The fabricated si/C60 multilayers with two pairs of 70 nm C60 and 30 nm si layers exhibit a PBG at central wavelength of about 600 nm, and the highest re？ectivity can reach 99%. As a consequence, this photonic crystal may be important for fabricating a photonic crystal with an incomplete band gap in the visible frequency range.

关键词： fullerene si multilayer films photonic band gap TMM method

si含量对高碳贝氏体钢微观组织与性能的影响

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金属热处理 2023年第9期48卷 165-173页

作者：戴钊郭智龙晓燕冯晓勇刘伟张福成李艳国燕山大学亚稳材料制备技术与科学国家重点实验室河北秦皇岛066004 秦皇岛港股份有限公司第七港务分公司河北秦皇岛066004 广州航海学院轮机工程学院广东广州510725 华北理工大学冶金与能源学院河北唐山063210

以4种不同si含量的高碳贝氏体轴承钢为研究对象,在相同热处理条件下,通过热膨胀相变仪、X射线衍射仪、扫描电镜和透射电镜等技术研究si含量对高碳贝氏体轴承钢相变、组织特征及力学性能的影响。结果表明,si能够延长高碳贝氏体轴承钢贝... 详细信息

以4种不同si含量的高碳贝氏体轴承钢为研究对象,在相同热处理条件下,通过热膨胀相变仪、X射线衍射仪、扫描电镜和透射电镜等技术研究si含量对高碳贝氏体轴承钢相变、组织特征及力学性能的影响。结果表明,si能够延长高碳贝氏体轴承钢贝氏体转变孕育期,降低贝氏体转变速率并提高Ac_(1)、Ac_(cm)温度。随着钢中si含量的增加,高碳贝氏体轴承钢中残留奥氏体体积分数增大,但贝氏体铁素体板条尺寸减小;当si含量达到1.4%时,贝氏体铁素体板条尺寸达到纳米级且板条内无碳化物析出。力学性能结果表明,高碳贝氏体轴承钢硬度随si含量的增加而降低,冲击性能随si含量的增加而升高,si含量为1.4%时高碳贝氏体轴承钢具有最佳的综合力学性能。

关键词： si 高碳贝氏体钢显微组织硬度冲击吸收能量

Plasma enhanced diamond deposition on steel and si substrates

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Acta Metallurgica sinica(English Letters) 2009年第5期22卷 321-329页

作者： Y.S. Li Y. Tang Wo Chen Q. Yang C.Xiao A. Hirose Plasma PhYsics Laboratory University of Saskatchewan Saskatoon SK S7N 5E2 Canada Department of Mechanical Engineering University of Saskatchewan Saskatoon S7N 5A9 Canada

Diamond growth on Fe-Cr-Al-si steel and si substrates was comparatively investigated in microwave plasma enhanced chemical vapor deposition （MPCVD） reactor with different deposition parameters. Adherent nanocrystalline diamond films were directly deposited on this steel substrate under a typical deposition condition, whereas microcrystalline diamond films were produced on si wafer. With increasing CH4 concentration, reaction pressure, or the total gas flow rate, the quality of nanocrystalline diamond films formed on Fe-Cr-Al-si substrates is gradually deteriorated in terms of density and adhesion. This impaired diamond quality on steels is primarily associated with a combined effect by the substrate composition and the specific process conditions that favor excessive nucleation of diamond.

关键词： Plasma CVD Diamond film Steel si

Corrosion behavior of hypereutectic Al-23%si alloy (AC9A) processed by severe plastic deformation

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Transactions of Nonferrous Metals Society of China 2010年第2期20卷 195-200页

作者：江静华马爱斌宋丹 N. SAITO 袁玉春 Y. NISHIDA College of Materials Science and Engineering Hohai University Nanjing 210098 China National Institute of Advanced Industrial Science and Technology 2266-98 Anagahora Shimoshidami Moriyama-ku Nagoya 463-8560 Japan

Ultrafine-grained(UFG) hypereutectic Al-23%si (mass fraction) alloy was achieved through equal-channel angular pressing(EACP) procedure. And the electrochemical properties after various ECAP passes were investigated in neutral NaCl solution. Potentiostatic polarization curves show that the corrosion potential of the ECAPed sample after 4 passes decreases markedly, while the corrosion current density reaches 1.37 times that of the as-cast alloy. However, the φcorr and Jcorr values after 16 passes are improved and approach those of the as-cast alloy. Immersion tests also show that the mass-loss ratio of ECAPed alloy decreases with increasing the pressing pass, which is lowered to 28.7% with the increase of pass number from 4 to 16. Pitting susceptibility of the ECAPed alloy after initial 4 passes is boosted, due to the presence of biggish voids resulted from the breakage of brittle large primary silicon crystals during ECAP. Increasing ECAP pass makes the voids evanesce and results in the homogeneous ultrafine-grained structure, contributing to a higher pitting resistance. These results indicate that enough ECAP passes are beneficial to increasing corrosion resistance of the hypereutectic Al-23%si alloy.

关键词：铸态合金变形加工过共晶腐蚀行为 Al si 超细晶结构塑性

Heterostructured graphene quantum dot/WSe2/si photo-detector with suppressed dark current and improved detectivity

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Nano Research 2018年第6期11卷 3233-3243页

作者： Mengxing Sun Qiyi Fang Dan Xie Yilin Sun Liu Qian Jianlong Xu Peng Xiao Changjiu Teng Weiwei Li Tianling Ren Yanfeng Zhang Institute ofMicroelectronics & Tsinghua National Laboratory for Information Science and Technology (TNList) Tsinghua University Beijing 100084 China Department of Materials Science and Engineering College of Engineering Peking University Beijing 100084 China Department of Chemistry Tsinghua University Belling 100084 China Institute of Functional Nano & Soft Materials (FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices Soochow University Suzhou 215123 China

A high-performance heterojunction photodetector is formed by combining an n-type si substrate with p-type monolayer WSe2 obtained using physical vapor deposition. The high quality of the WSe2/si heterojunction is demonstrated by the suppressed dark current of I nA and the extremely high rectification ratio of 107. Under illumination, the heterojunction exhibits a wide photoresponse range from ultraviolet to near-infrared radiation. The introduction of graphene quantum dots （GQDs） greatly elevates the photodetective capabilities of the heterojunction with strong light absorption and long carrier lifetimes. The GQDs/WSe2/si heterojunction exhibits a high responsivity of -707 mA·W^-1, short response time of 0.2 ms, and good specific detectivity of -4.51×10^9 Jones. These properties suggest that the GQDs/WSe2/si heterojunction holds great potential for application in future high- performance photodetectors.

关键词： heterojunction photodetector si WSe2 graphene quantum dots

Reconstruction of broken si–O–si bonds in iron ore tailings (IOTs) in concrete

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International Journal of Minerals,Metallurgy and Materials 2019年第10期26卷 1329-1336页

作者： Juan-hong Liu Yu-cheng Zhou Ai-xiang Wu Hong-jiang Wang School of Civil and Resource Engineering University of Science and Technology BeijingBeijing 100083China Beijing Key Laboratory of Urban Underground Space Engineering University of Science and Technology BeijingBeijing 100083China State Key Laboratory of High-efficient Mining and Safety of Metal Mines Ministry of EducationUniversity of Science and Technology BeijingBeijing 100083China

This paper reports a study on the reconstruction of broken si O si bonds in iron ore tailings (IOTs) in concrete. Limestone and IOTs were used to investigate the influence of different types of coarse aggregates on the compressive strengths of concrete samples. The dif- ferences in interfacial transition zones (ITZs) between aggregate and paste were analyzed by scanning electron microscopy (SEM) and ener- gy-dispersive spectroscopy (EDS). Meanwhile, X-ray diffraction (XRD) and infrared spectroscopy (IR) were used to study microscopic changes in limestone and IOTs powders in a simple alkaline environment that simulated cement. The results show that the compressive strengths of IOTs concrete or paste are higher than those of limestone concrete or paste under identical conditions. The Ca/si atom ratios in the ITZs of IOTs con- crete samples are lower than those of limestone concrete;the diffraction peak of the calcium silicate phase at 2θ = 29.5°, as well as the bands of si O bonds shifting to lower wavenumbers, indicates reconstruction of the broken si-O-si bonds on the surfaces of IOTs with Ca(OH)2.

关键词： iron ore tailings broken si O si bonds alkaline environment reconstruction

Characteristics of In_(0.52)Al_(0.48)As Grown on InP(100) Substrates by Molecular Beam Epitaxy: Growth Optimisation and Effects of si Doping

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Journal of Materials Science & Technology 1997年第2期13卷 91-98页

作者： S.F.Yoon(School of Electrical and Electronic Engineering, Nanyang Technological University, Nanyng Avenue,singapore 639798, Rep. of singapore) School of Electrical and Electronic Engineering Nanyang Technological University Nanyang Avenue Singapore 639798 Singapore

Growth of In0.52Al0.48As epilayers on InP (100) substrates by molecular beam epitaxy at a wide range of substrate tempreatures (470~550℃) and at different si doping levels has been carried out. Low temperature photoluminescence (PL) and double-axis X-ray diffraction (XRD) analyses shaw a strong dependence of the PL and XRD linewidths, XRD intensity ratio (Lepi/Isub), and lattice-mismatch on the substrate temperature. The X-ray diffraction peaks of samples grown at law temperatures show a composition of smaller peaks, indicating the presence of disorder due to alloy clustering. Raman scattering measurements of the same samples show an additional higher energy mode at 273 cm-1 in addition to the InAs-like and AlAs-like longitudinal-optic (LO) phonon modes. Samples doped with si show an inverted S-shaped dependence of the PL peak energy variation with the temperature which weakens at high doping levels due to a possible reduction in the donor binding energy. Supported be observations of a reduction in both the AlAs-like and InAs-like LO phonon frequencies and a broadening of the LO phonon line shape as the doping level is increased, the PL intensity also shows in increasing degrees at higher doping levels, a temperature dependence which is characteristic of disordered and amorphous materials.

关键词： As Grown on InP Characteristics of In Growth Optimisation and Effects of si Doping Substrates by Molecular Beam Epitaxy InP Al si

Properties of the Environmental-Friendly si/Al Composite for Electronic Packages Fabricated by Squeeze Casting Technology

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上海交通大学学报 2007年第S2期41卷 144-149页

作者：武高辉修子扬张强 School of Materials Science and Eng. Harbin Institute of Technology

High reinforcement-content aluminum matrix composite,with a high thermal conductivity,the adjustable coefficient of thermal expansion(CTE),low density and costs,have been extensively applied in electronic package.The sip/Al composites were fabricated by squeeze casting technology.The microstructure observation showed that the composites were dense and macroscopically homogeneous,with no micro-holes and obvious defects.The linear CTEs of sip/Al composites lay between(7.6～8.1)×10^-6 ℃^-1,and the thermal conductivity was larger than 100 W/(m·℃).The composites also had lower density(2.4 g/cm^3),higher special strength and special modulus.The electroless nickel method was used to deposit a continuous and uniform layer on the composites surface,which can meet the reliability testing demands of the diodes with sip/Al composite baseplate.

关键词： si particles aluminum matrix composite thermal expansion thermal conductivity

Characterization of a-si:H/siN multilayer waveguide polarization using an optical pumping application—LED

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第10期10卷 1421-1427页

作者： Mohd Saiful Dzulkefly ZAN Isamu KATO Mohammad Syuhaimi AB-RAHMAN Seri Mastura MUSTAZA Department of Electrical Electronic and System EngineeringFaculty of Engineering and Built EnvironmentUniversiti Kebangsaan Malaysia Department of Electrical Engineering and Bioscience Waseda University

This paper describes the fabrication of a waveguide and the analysis of its polarization characteristics by applying light-emitting diode(LED) pumping lights to its surface.By using double tubed coaxial line(DTCL) microwave plasma chemical vapor deposition(MPCVD) equipment,an a-si:H/siN multilayer waveguide was fabricated whose thickness could be controlled at nanometer order.The main structural material of the waveguide sample consisted of a combination of layers of amorphous silicon hydrogen and silicon nitrate.Once the sample was ready,another major objective of the experiment was to analyze the polarization characteristics of the fabricated waveguide.The idea of the experiment was to analyze how the waveguide reacts when three types of LED(blue,yellow,and red) are radiated onto its surface.The results showed that the fabrication of the a-si:H/siN sample is successful.Most effective transmission results,which accord with the polarization characteristics analysis,were obtained.

关键词：多层波导 LED 微波等离子体化学气相沉积法氮化 si 应用抽水光偏振