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Studies on the microstructure,optical and electrical properties of organic microcavity devices based on a porous silicon reflector

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Science China(Technological Sciences) 2005年第2期48卷 191-201页

作者： XIONG Zuhong1, FAN Yongliang2. ZHAN Yiqiang2. ZHANG Songtao2. DING Xunmin2.& HOU Xiaoyuan2.1. School of physics, Southwest China-Normal University, Chongqing 400715, China 2. surface physics Laboratory (National key Laboratory), Fudan University, Shanghai 2.0433, China 1. School of physics Southwest China-Normal University 400715 Chongqing China 2. surface physics Laboratory (National {2. Laboratory) Fudan University 200433 Shanghai China

A novel type of microcavity organic light-emitting diode based on a porous silicon distributed Bragg reflector (PS-DBR) has first been achieved and its microstructure, optical, and electrical properties have also been investigated in detail. The microcavity is made up of the central active organic multilayer sandwiched between a top silver film and a bottom PS-DBR, formed by electrochemical etching of p++-Si substrate. The field- emission scanning electron microscopy cross-section images show the nanometer-scale layered structure and flat interfaces inside the microcavity. The reflectivity (relative to an Al mirror) of the PS-DBR is up to 99%, and the stopband is about 160 nm wide. Resonant cavity mode appears as a tip in the reflectivity spectrum of the Si-based organic multilayer films, which is a symbol that the Si-based organic multilayer structure is indeed a microcavity. The peak widths of the electroluminescence (EL) spectra from the cavities emitting green and red light are greatly reduced from 85 nm and 70 nm to 8 nm and 12.nm, respectively, as compared with those measured from non-cavity structures. Note that the EL emission from the cavity devices is single-mode, and the off-resonant optical modes are highly suppressed. Moreover, increases of a factor of about 6 and 4 of the resonant peak intensity from the cavities emitting green and red light are also observed, respectively. In addition, the current-brightness-voltage characteristics and effect parameters on the lifetime of the cavity devices are also discussed. The present technique for obtaining enhanced EL emission from Si-based organic microcavity may also be another novel effective method for realizing Si-based optoelectronics device integration.

关键词： electrochemical etching, Si-based microcavity, electroluminescence, organic light-emitting diodes.

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Preparation of InSb nanocrystals embedded in SiO_2.thin films

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Chinese Science Bulletin 1998年第19期43卷 1610-1615页

作者： ZHU Kaigui 1, SHI Jianzhong 1, WEI Yanfeng 2.and ZHANG Lide 1 1. Institute of Solid State physics, Chinese Academy of Science, Hefei 2.0031, China 2. State key Laboratory of {2. physics, Fudan University, Shanghai 2.0433, China Institute of Solid State physics Chinese Academy of Science Hefei China State key Laboratory of surface {2. Fudan University Shanghai China

InSb nanocrystals embedded in SiO 2.thin films were prepared by rf magnetron cosputtering technique. THe observation by transmission electron microscope showed that InSb nanocrystals dispersed uniformly in SiO-2.matrices. InSb nanocrystals with different sizes can be obtained by changing the annealing condition. The average size of InSb nanocrystals depended on annealing temperature and time, but not on the t 1/3 rules. X-ray photoelectron spectroscopy and X-ray diffraction were also applied to the analyses of the composite thin films.

关键词： InSb nanocrystals radio-frequency sputtering quantum confinement.

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Density-functional theory study of the effect of pressure on the elastic properties of CaB_6

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Chinese physics B 2013年第7期22卷 420-425页

作者：韩晗 surface physics Laboratory (National {2. Laboratory) Key Laboratory of Computational Physical Sciencesand Department of PhysicsFudan University

Under high pressure, the long believed single-phase material CaB6 was latterly discovered to have a new phase tI56. Based on the density-functional theory, the pressure effects on the structural and elastic properties of CaB6 are obtained. The calculated bulk, shear, and Young’s moduli of the recently synthesized high pressure phase tI56-CaB6 are larger than those of the low pressure phase. Moreover, the high pressure phase of CaB6 has ductile behaviors, and its ductility increases with the increase of pressure. On the contrary, the calculated results indicate that the low pressure phase of CaB6 is brittle. The calculated Debye temperature indicates that the thermal conductivity of CaB6 is not very good. Furthermore, based on the Christoffel equation, the slowness surface of the acoustic waves is obtained.

关键词： density-functional theory elastic properties pressure effects acoustic properties

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SPUTTERING BEHAVIOUR OF IRON SILICIDES UNDER LOWENERGY Ar^+ ION BOMBARDMENT

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Acta Metallurgica Sinica(English Letters) 1999年第6期12卷 0-0,0-0+0-0页

作者： Z.X. Cao E.G. Wang and YX. Ne(State key Laboratory for surface {2., Institute of {2., Beijing 100080, China)

surface compositions of Fe3Si, FeSi and FeSi2.under 0.1 to 5ke V Ar+ bombaniment have been investigated by using AES method, and the results indicate that the sudece compositions depend strongly on ion enerpy and sample bulk compositions. While in FeSi and FeSi2.only Fe enrichment in the selvage has been observed, in Fe3Si it is Si enriched when the ion enerpy is higher than 31OeV Competition between preferential sputtering and radiation enhanced segmpation is quoted to eoplain this phenomenon.

关键词： preferential sputtering iron silicides radiation enhanced segregation

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Magnetron sputtering synthesis of large area well-ordered boron nanowire arrays

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Science China(physics,Mechanics & Astronomy) 2004年第4期47卷 403-415页

作者： CAO Limin1,2. ZHANG Ze2.& WANG Wenkui1,2.1. key Laboratory of Metastable Materials Science and Technology and College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004, China 2. Institute of physics, Chinese Academy of Sciences, Beijing 100080, China 1. key Laboratory of Metastable Materials Science and Technology and College of Materials Science and Engineering Yanshan University 066004 Qinhuangdao China 2. Institute of physics Chinese Academy of Sciences 100080 Beijing China

One-dimensionally nanostructured materials, such as nanowires and nanotubes, are the smallest dimensional structures for efficient transport of electrons and excitons, and are therefore critical building blocks for nanoscale electronic and mechanical devices. In this paper, boron nanowires with uniform diameters from 2. to 80 nm were synthesized by radio-frequency magnetron sputtering of pure boron powder and B2.3 powder mixtures in argon atmosphere. The boron nanowires produced stand vertically on the substrate surface to form well-ordered arrays over large areas with self- organized arrangements without involvement of any template and patterned catalyst. The high-density boron nanowires are parallel to each other and well distributed, forming highly ordered and uniform arrays. A more interesting and unique feature of the boron nanowires is that most of their tips are flat rather than hemispherical in morphologies. Detailed studies on its structure and composition indicate that boron nanowires are amorphous. Boron nanowire appears as a new member in the family of one-dimensional nanostructures. Considering the unique properties of boron-rich solids and other nanostructures, it is reasonable to expect that the boron nanowires will display some exceptional and interesting properties. A vapor-cluster-solid (VCS) mechanism was proposed to explain the growth of boron nanowires based on our experimental observations.

关键词： boron nanowires, magnetron sputtering, arrays, self-assembly.

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Friction-reducing and antiwear behavior of metal halide-stabilized linear phosphazene derivatives as lubricants for a steel-on-steel contact

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Science China(Technological Sciences) 2005年第3期48卷 282-291页

作者： ZHU Jiamei 1,2., LIU Weimin 2.& LIANG Yongmin 2.1. School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 2.1008, China 2. State key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical physics, Chinese Academy of Sciences, Lanzhou 730000, China 1. School of Chemical Engineering and Technology China University of Mining and Technology 221008 Xuzhou China 2. State key Laboratory of Solid Lubrication Lanzhou Institute of Chemical Physics Chinese Academy of Sciences 730000 Lanzhou China

A series of novel metal halide-stabilized linear phosphazene derivatives were synthesized. The friction-reducing and antiwear abilities of the resulting products as the lubricants for a steel-on-steel contact were comparatively investigated on an Optimol SRV oscillating friction and wear tester. The morphology of the worn steel surface was observed on a scanning electron microscope, while the chemical states of some typical elements on the worn steel surface were examined by means of X-ray photoelectron spectroscopy. It was found that both the side branch structures and central metals influenced the friction-reducing and antiwear behaviors of the synthetic derivatives as the lubricants, which was related to the different adsorption activities of the organic compounds composed of different organic ingredients and metallic ions on a nascent metal surface. All the synthetic lubricants except for the iron (III) derivative showed increased antiwear abilities with increasing metallic ionic radius. A protective layer originated from the tribochemical reaction together with the adsorbed boundary lubricating layer containing organic fluorine compounds, nitrogen oxide, and Fe 3 (PO 4 ) 2.plays an important role in improving the friction and wear behavior of the steel-on-steel system.

关键词： metal halide-stabilized linear phosphazene derivatives,lubricant,steel,tribological properties.

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Peculiar dynamical properties of plutonium hydrides

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Progress in Natural Science:Materials International 2006年第3期16卷 248-254页

作者： MENG Daqiao, ZHU Zhenghe, LUO Deli and JIANG Gang (Institute of Atomic and Molecular physics, Sichuan University, Chengdu 610065, China National key Laboratory of {2. physics and Chemistry, Mianyang 62.907, China) [a]Institute of Atomic and Molecular physics Sichuan University Chengdu China [b]National key Laboratory of surface {2. and Chemistry Mianyang China

In the present work, the structure and spectra of PuH and PuH2.are defined by B3LYP/SDD method, from which the analytic potential energy function of PuH2.is derived. The analysis of quasi-classical molecular reaction dynamics is performed to study the state-state process of Pu(7Fg) + H2.X1∑g+). It is found that the reaction Pu(7Fg)+H2.X1∑g+)→PuH2.X7B1) has no threshold. The simultaneous hydrogenation process of plutonium with the main product of PuH2.is theoretically proved for the first time.

关键词： hydrogenation reaction of plutonium molecular dynamics density functional theory.

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Silicon nanoporous pillar array and its surface copper deposition

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Chinese Science Bulletin 2005年第14期50卷 1424-1428页

作者： FU Xiaonan1,2.3, CHAI Huadou1,2.& LI Xinjian1,2.1. Department of physics, Zhengzhou University, Zhengzhou 450052. China 2. key Laboratory of Material physics (Zhengzhou University), Ministry of Education, Zhengzhou 450052. China 3. Department of Mathematics and physics, Henan University of Tech- nology, Zhengzhou 450052. China Department of physics Zhengzhou University Zhengzhou 450052 China key Laboratory of Material physics (Zhengzhou University) Ministry of Education Zhengzhou 450052 China Department of Mathematics and physics Henan University of Technology Zhengzhou 450052 China

Silicon nanoporous pillar array (Si-NPA) has been prepared by a hydrothermal etching technique. Using Si-NPA as substrate, a Cu/Si-NPA nanocomposite thin film has been obtained with immersion plating method. Morpho- logical and structural analysis indicates that Si-NPA is a typical structural composite system characterized by a triple hierarchical structure, i. e. the array of micron-sized silicon pillars, the nanopores densely distributed on the surface of the pillars, and the silicon nanocrystallites that constitute the pore walls. Cu/Si-NPA inherits the morphological character- istics of Si-NPA. The compactability of the deposited copper nanoparticles varies alternatively with the local geometrical features of Si-NPA and forms a quasi-periodical pattern. Such an experimental phenomenon is attributed to the veloc- ity dependence of the copper deposition upon the local geo- metrical features of Si-NPA. These results indicate that Si-NPA might be used as an ideal template for preparing specially patterned, structured or functionalized metal/ sili- con nanocomposite systems.

关键词：硅元素薄膜蚀刻技术电镀技术

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TURNING-OVER OF THE ELECTRIC DIPOLE IN A POLYMER

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Chinese Journal of Polymer Science 2001年第6期19卷 573-578页

作者： Guang-qi Li Xin Sun and Sheng Li State key Laboratory of surface {2. and Research Center for Theoretical {2., Fudan University Shanghai 2.0433, China National Laboratory of Infrared {2., Shanghai Institute of Technical {2.,Shanghai 2.0083, China Fudan Univ State Key Lab Surface Phys Shanghai 200433 Peoples R China Fudan Univ Res Ctr Theoret Phys Shanghai 200433 Peoples R China Acad Sinica Shanghai Inst Tech Phys Natl Lab Infrared Phys Shanghai 200083 Peoples R China

The transition from the biexciton to the exciton can turn over the direction of the electric dipole of a polymericmolecule. This turning-over action combined with the photoinduced polarization reversion can be used as a switch. Theswitching speed is governed by the relaxation time of the turning-over process, which can be determined by a dynamicalsimulation.

关键词： exciton biexciton electric dipole switch relaxation

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Interfacial behaviors of PMMA-PEO block copolymers at the air/water interface

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Science China Chemistry 2005年第6期48卷 567-573页

作者： CHENG Caixia1, JIAO Tifeng2. TANG Rupei1, LIU Minghua2.& XI Fu1 1. State key Laboratory of Polymer physics and Chemistry, Joint Laboratory of Polymer Science and Materials, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China 2. CAS key Laboratory of Colloid and Interface Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China 1. State key Laboratory of Polymer physics and Chemistry Joint Laboratory of Polymer Science and Materials Institute of Chemistry Chinese Academy of Sciences 100080 Beijing China 2. CAS key Laboratory of Colloid and Interface Science Institute of Chemistry Chinese Academy of Sciences 100080 Beijing China

Diblock copolymer of PMMA2.1-b-PEO114 and triblock copolymer of PMMA12.-b- PEO2.7-b-PMMA12. were synthesized and their interfacial properties at the air-water interface were investigated, where both blocks of polyethylene oxide (PEO) and poly(methyl methacrylate) (PMMA) are surface active but the former is soluble in water while the latter is not. Both the block copolymers could form monolayers with two obvious transition regions. The first transition point is around 10 mN/m, which could be assigned to the pancake-brush change of the PEO chains. The other is around 18 mN/m, which could be ascribed to the condensed packing of PMMA. The surface morphological changes during the compression of the Langmuir monolayers are inves-tigated by using the AFM and SEM methods for the films deposited at different surface pressure or molecular areas. At a lower surface pressure, a typical morphology of PEO-con- taining lipopolymers is observed. Upon compression, sphere-dominant morphologies were observed. While the diblock copolymer is easy to folding, the triblock copolymer is in favor of formation of circular domains through vesiculation.

关键词： PMMA-PEO, block copolymers, monolayer, Langmuir-Blodgett films, AFM.

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