bluuebunny/crossref_metadata_2025 huggingface dataset:
Magnetic Properties of Ferrous Ferric Oxide Confined in Porous Silicon
Authors: Huang Yuan Ming , Zhai Bao Gai , Ma Qing Lan , Meng Ming
Published: November 2010

During the chemical synthesis nanometer-sized particles of ferrous iron oxide were in situ infiltrated into the mesopores in a porous silicon film. The microstructures of porous silicon and the magnetic properties of the nanometer-sized particles of the ferrous iron oxide were characterized with scanning electron microscopy, X-ray diffractometry, and the hysteresis loop measurement, respectively. Our results have demonstrated that the magnetic properties of the nanometer-sized Fe3O4 particles can be dramatically modified when they are confined into the mesopores of the porous silicon film.
Synthesis of Nickel Hydroxide with Different Morphologies Using an Ionic Liquid
Authors: Xu Cun Ying , Hua Yi Xin
Published: November 2010

A new and facile route has been developed to synthesize β-Ni(OH)2 nanostructures using ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF4) as reaction media under solvothermal conditions. The β-Ni(OH)2 with different morphologies, such as nanoflakes, nanoplatelet and nanorods, can be obtained by controlling the volume ratio of the ionic liquid to water and reaction temperature. The as-prepared products were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM).
Phosphorus Content Dependent Sliding Wear Behaviors of Electroless Ni-P Deposits
Authors: Cheng Yan Hai , Zhu Zhen Cai , Han Zheng Tong , Zou Yong
Published: November 2010

In this work, the deposits of electroless Ni-P deposits prepared by different process were studied by means of EPMA, mirohardness tester, friction-wear instrument. The experimental results showed that the microhardness of the deposits was directly affected by the phosphorus content, which was depended on the processes of electroless. The friction-wear tests showed that the Ni-P deposits composing of less phosphorus content exhibited lower friction coefficient before and after being heat treated. The conclusion was drawn that the lower phosphorus content deposits could improve the wear resistance under the condition of both as-plated and after being heat treated Ni-P deposits. The wear behavior was typical of a pure adhesive wear mechanism for the high phosphorus content deposit at as-plated and after being heat treated at 200oC. However, for the high phosphorus content deposit after being heat treated at 400oC, the alternate friction mechanisms were emerged from adhesive wear to abrasive wear with the precipitating of hard Ni3P particles during Ni-P deposits suffering friction tests
Applications of GPRS in the Mine Monitoring and Control System
Authors: An Ji Yu , Zhang Li , Ma Song Bo
Published: November 2010

With the development of GPRS technology in the field of mobile communication, GPRS has been used in the system of radio data transmission at present. This paper explores the applications of GPRS in the mine monitoring and control system. In this paper we have done three things. we talk about the core cutting and moving and the system structure. we give a plan to realize the GPRS communication.
Effect of Different Reaction Solvents on the Hydrophobic and Structural Properties of Silica Cryogels
Authors: Su Li Fen , Miao Lei , Tanemura Sakae , Xu Gang
Published: November 2010

The experimental results on the microstructural and physical properties of the TEOS-based silica cryogels have been reported. The cryogels were produced by two-step sol-gel process followed by vacuum freeze drying. The wet gels were synthesized via acid-base catalysis using tetraethoxysilane (TEOS) as a silica precursor, the different solvents containing ethanol (EtOH), methanol (MeOH) and tert-butanol (TBA), the molar ratio of TEOS / solvent were varied from 1:6 to 1:13. Further, the microstructure and specific surface area of the cryogels were analysed by Scanning Electron Microscopy (SEM) and nitrogen absorption/desorption isotherms. The hydrophobicity of the cryogels was studied by contact angle. It was found that the highest specific surface area (1040.17 m2 / g) was obtained with the solvent of MeOH. The lowest density (0.074 g/cm3) was acquired with the solvent of EtOH.
Synthesis and Magnetic Properties of CoAl2O4 Coated Co Solid Solution Nanocapsules
Authors: Shi Gui Mei , Song Ge , Lian Shu , Zhang Jin Bing
Published: November 2010

A new type of antiferromagnetic CoAl2O4 coated ferromagnetic Co solid solution is synthesized by arc-discharging. Typical HRTEM images show that the nanocapsules form in a core-shell structure. The size of the nanocapsules is in range of 10-90 nm and the thickness of the shell is about 3-10 nm. X-ray photoelectron spectrum (XPS) and X-ray diffraction (XRD) reveal that the core consists of Co solid solution, while the shell is CoAl2O4. The magnetic field and temperature dependence of magnetizations confirm that the Co solid solution nanocapsules are basically in the ferromagnetic state below Curie temperature. In addition, the antiferromagnetic order occurs with Neél temperature TN of about 5 K. The saturation magnetization of Ms = 76.1 Am2/kg and the coercive force of Hc= 23.28 kA/m are achieved at room temperature for the Co solid solution nanocapsules.
Effects of Heat Treatment on Growth of BaSi2 Film on Si(111) Substrates
Authors: Yang Zi Yi , Hao Zheng Tong , Xie Quan
Published: November 2010

Semiconducting orthorhombic BaSi2 films were synthesized on Si(111) substrates using magnetron sputtering (MS) and subsequent annealing by interdiffusion between the deposited Ba film and Si(111) substrate. The structural and morphological features of the result films are analysed. The growth mechanism and the evolution of the silicides are discussed. The effects of annealing temperature and annealing time on the growth of the BaSi2 film are studied.
The Phase Composition of Re3+ (Re=Lu, Gd, La) Co-Doped YAG:Ce and its Luminescent Properties
Authors: Zhang Le , Yang Hao , Han Peng De , Wang Li Xi , Zhang Qi Tu
Published: November 2010

A series of Re3+ (Re=Lu, Gd, La) co-doped YAG phosphors were successfully synthesized by a sol-gel combustion method and characterized with XRD and photoluminescent spectrum. The phase composition and luminescent properties of YAG:Ce under different Re co-doped concentrations were investigated. Doping only 50 mol% of La3+ to replace Y3+ sites, the main phase of sample has transformed into LaAlO3. While the concentration of Gd3+ reached 90~99 mol%, it was still cubic YAG. Lu3+ could replace Y3+ ions completely with the garnet structure. The location of the emission peak of Gd-codoped YAG:Ce3+ shifted to red region 21 nm corresponding to the maximum emission intensity before the appearance of GdAlO3. In addition, it had a 24 nm blue shift when Y3+ replaced by Lu3+ completely.
Effect of Substrate Temperature on the Properties of Al-Doped ZnO Films by RF Magnetron Sputtering
Authors: Wu Yue Bo , Lei Sheng , Wang Zhe , Zhao Ru Hai , Huang Lei , Li Hui
Published: November 2010

The Al-doped ZnO (AZO) films were deposited on the glass substrates by RF magnetron sputtering at different substrate temperatures. The effect of substrate temperature on the structural, optical, and electrical properties of AZO films was investigated. The results indicate each of the films has a preferential c-axis orientation. The grain size increases with substrate temperature increasing. All the films exhibit a high transmittance in visible region and have sharp ultraviolet absorption characteristics. The resistivity decreases with substrate temperature increasing up to 250oC, then increases for higher temperature.
Simulation Study of Microstructure Transition of Liquid Ge during Rapid Cooling Solidification
Authors: Zhu Chang Yin , Xie Quan
Published: November 2010

Structural and dynamical properties of the rapid solidification process of liquid Ge have been investigated by molecular-dynamics calculations based on the Stillinger-Weber potential. The variations of microstructures during the solidification process are analyzed by the self-diffusion coefficient D(T), pair correlation function g(r) curves and the HA bond-type index method. The melting point implicated in D(T) is about 2100 K. The pair correlation function g(r) obtained by the simulated in liquid Ge is good agreement with experiment, the fist-peak of g(r) gradually becomes higher and sharper with the temperature decreasing, when temperature drops to 1400 K, the second-peak of g(r) begins to split. The change of HA bond-type indicated that the most important structural change occurs in the temperature range 1400 K-700 K.
Investigation on Preferential Chemical Etching of Dislocations in Sapphire
Authors: Xie Xin Jian , Li Yin Ying , Wang Min , Liang Li Min , Hao Qiu Yan , Liu Cai Chi
Published: November 2010

In this work, the pits were successfully etched on the (001) sapphire single crystal surface. The experiments were processed by using fused KOH etchant at different temperature about 15 minutes. The difference in the morphology of etching pits on c plane sapphire was observed by metallurgical microscope and atomic force microscopy. It was found that the size of etch pits would be increasing if the temperature high enough. And the density of etch pits had a maximum at about 320°C.Finally, it was put forward and discussed that three kinds of mechanisms about the etching pits based on the experimental fact: annexed, merger, expansion.
Synthesis and Characterization of Superparamagnetic NiFe2O4 Nanoparticles
Authors: Sun De Hui , Sun De Xin , Hao Yu
Published: November 2010

The superparamagnetic NiFe2O4 nanoparticles were synthesized using a hydrothermal technology through P123 sphere micelles as ‘nanoreactor’ in this work. Their morphologies, structures, surface properties and magnetism were characterized by FE-SEM, XRD, FTIR, and VSM, respectively. The nickel ferrite samples are nearly spherical and homogeneous nanoparticles with average size range of about 50-120 nm. They possess superparamagnetism at room temperature and higher saturation magnetization. X-ray diffraction (XRD) pattern confirms that the samples belong to the cubic crystal system with an inverse-spinel structure. Fourier transform infrared (FTIR) absorption spectrum indicates that the NiFe2O4 nanoparticles are stabilized by the P123 adsorbed on the surface of nanoparticles.
The Luminescence Properties of BaGd2(MoO4)4: Eu3+, Er3+, Yb3+ Phosphors
Authors: Sun Jia Yue , Zhang Wei Hang , Lan Yu Jing , Du Hai Yan
Published: November 2010

Two-color emission phosphors BaGd2(MoO4)4: Eu3+, Er3+, Yb3+ have been synthesized by the high temperature solid-state method. The as-prepared BaGd2(MoO4)4: Eu3+, Er3+, Yb3+ phosphors can emit intense red light under 395 nm UV excitation, while it will show bright green light upon 980 nm infrared light excitation. It is found that the red emission peaks at 595 and 614 nm should be attributed to 5D0-7F1 and 5D0-7F2 transitions of Eu3+, respectively. The green emission peaks centered at 532 and 553 nm under 980 nm excitation, are attributed to Er3+ transitions from 4H11/2 -4I15/2 and 4S3/2-4I15/2, respectively.
Reflectance of Micro-Structural Material on Au
Authors: Feng Guo Jin , Li Ping , Wang Yu , Li Cheng , Zhao Li
Published: November 2010

The high absorption characteristics, the complex mechanism and the great potential application in detectors of micro-structural material aroused extensive attention. In order to understand the impact of the micro-structure, the optical simulation method based on Monte Carlo is used for reflection characteristics of micro-structural material with the cell of pyramid construction. In this simulation, the body material is made of gold, which can avoid the effect of tranmittance, with a number of 400 cells. The bottom square of each structure is 50×50 µm, and the height of cells is adjustable. Then the relationship between the height and reflectance can be built up. However, a very complex relationship between the reflectance and the input parameters, including refractive index, extinction coefficient and the structure of the material is showed from simulation result. Generally, the reflectance decreases while the height increases.
Influence of Flux on Morphological and Luminescent Properties of Y3Al5O12:Tb3+ Phosphor
Authors: Yu Quan Mao
Published: November 2010

The Y3Al5O12: Tb3+ phosphors are synthesized by solid-state reaction method using fluxes of LiF, NaF, MgF2, AlF3, CaF2, SrF3, KH2PO4 and complex fluxes of LiF+AlF3, KH2PO4+LiF separately. The influence of fluxes on phosphors morphology and luminescent properties are investigated by SEM, HITACHI F-450 photometer and cathodoluminescent photometer. The results indicate that KH2PO4 can improve the morphology characteristics of the phosphors, but LiF, AlF3, NaF, MgF2, SrF3, CaF2 are unavailable. LiF, NaF, AlF3, KH2PO4 can improve the phosphors photoluminescent intensity more than 20 percent and cathodoluminescent intensity more than 10 percent. Using KH2PO4 as flux, excellent luminescent properties and well dispersed ~2 m spherical or sub-spherical YAG: Tb3+ phosphors can be synthesized under 1500 oC.
Surfacial Metallization of Carbon Fibers by Copper Coating and Field Emission Properties
Authors: Yang Lan , Ye Yun , Guo Tai Liang , Huang Xiao Jin
Published: November 2010

Carbon fibers (CNFs) were surfacial metallized by electroless deposited with copper, and their field emission properties were investigated by diode test. The results indicated that the field emission properties of CNFs were affected by the thicknesses of copper. After CNFs were surfacial metallized, the volume resistivity of CNFs was decreased and field emission property was increased, respectively; increase the thin-film thickness, there appeared an optimal film thickness value for properties of field electron emission. It was found that CNFs owned the best field emission properties after electroless depositing for 15 min, with copper metal thickness as 2.1 µm and the volume resistivity down to 2.3510-4 Ω•cm. The field emission tests showed when applied voltage was 562 V, CNFs appeared bright dots, and the high luminance achieved 1388 cd/m2 under applied voltage 1013 V. Further more theoretical analyses, copper coating on CNFs surface is attributed to good electric conductivity, the low work function and the lower attenuation of electron scattering in thin-film.
Kinetic Monte Carlo Simulation of the Flux Dependence of Semiconductor Quantum Dot Growth
Authors: Zhao Chang , Zhao Man , Wang Yi , Lv Ai Jun , Wu Guang Ming
Published: November 2010

Performing an event-based continuous kinetic Monte Carlo (KMC) simulation, all the important kinetic behaviors take place during the growth of the semiconductor material in the molecular beam epitaxy (MBE) system such as deposition, diffusion, desorption, and nucleation are considered, we investigate the effects of the growth conditions which are important to form semiconductor quantum dot (QD) in MBE system. The simulation results provide a detailed characterization of the atomic kinetic effects. The KMC simulation is also used to explore the effects of anisotropy effects to the epitaxy growth of QD. We find that the flux plays an important role in determining the size of the QD. The agreement between our simulation and experiment indicates that this KMC simulation is useful to study the growth mode and the atomic kinetics during the growth of the semiconductor QDs in MBE system.
Effect of Anionic Surfactants with Different Structure on the Fluorescent Properties of the CPPO-H2O2-Rhodamine B System
Authors: Du Hai Yan , Xu Wei Da , Zhou Wei , Sun Jia Yue
Published: November 2010

The effect of anionic surfactants on the chemiluminescence (CL) properties of CPPO- H2O2-Rhodamine B system was researched, and the maximum fluorescent intensity of every system was found at the critical micelle concentration (CMC) of corresponding surfactant. The reduced vibration of Rhodamine B molecules induced by the combination of micelle was offered to explain the positive effect of anionic surfactants. Moreover, the structure of anionic surfactant was found to be relative to the enhanced fluorescent intensity, and the hydrophobic group’s structure and stereospecific blockade were considered as two main factors to the sensitization ability of anionic surfactant on CL.
Synthesis and Characterization of Ternary Terbium Luminescence Complexes with Phthalic Acid and 1, 10-Phenanthroline
Authors: Ren Hui Juan , Sun De Hui , Cui Zhen Feng , Yang Hua , Hong Guang Yan
Published: November 2010

Ternary rare earth luminescence complexes composed of Tb (III)-phthalic acid (H2L)-1,10-phenanthroline (phen) were synthesized using precipitation method. The elemental analysis, plasma atomic emission spectra, infrared spectra were measured the composition of obtained samples and the chemical composition deduced is TbL3/2(phen)0.5. XRD patterns show that the obtained coordination compound is new crystal different from that of two ligands. SEM results indicate that the coordination compound is a floral crystal with the size about 1-2 µm and has better dispersity. The TG-DTA result showed that the luminescence complex has good stability below 478 oC. Photoluminescence analysis indicated that the coordination compound emits Tb3+ characteristic green luminescence under ultraviolet excitation.
Antimony Bismuth Alloy Films: Preparation, Optical and Thermal Properties
Authors: Lu Xin Miao , Wu Yi Qun , Wang Yang
Published: November 2010

Antimony bismuth alloy films were deposited on Si and K9 glass substrates by magnetron-control sputtering method. The structure of the film was studied with x-ray diffraction (XRD). The thermal property of the film was researched by differential scanning calorimetry (DSC). The optical constants of the films including refractive index (n) and extinction coefficients (k) are measured by ellipsometry, and the dielectric constants (=r+ii), absorption coefficients  were also calculated.
One-Step Anodization Preparation and Photoluminescence Property of Anodic Aluminum Oxide with Nanopore Arrays
Authors: Yang Wen Bin , Tang Xiao Hong
Published: November 2010

Anodic aluminum oxide (AAO) film with nanopore arrays was prepared by one-step anodization of highly pure aluminum foil. Morphology, structure and photoluminescence property of AAO were characterized. Results showed that AAO owned honeycomb structure which was characterized by close-packed arrays of columnar hexagonal cells, each containing a central pore normal to the substrate. There were three peaks at around 370, 385 and 470 nm in the PL spectrum of AAO, which should be mainly attributed to the oxygen vacancies.
Fluorescence Gas Sensor Using CdTe Quantum Dots Film to Detect Volatile Organic Compounds
Authors: Bakar Norhayati Abu , Rahmi Aidhia , Umar Akrajas Ali , Salleh Muhamad Mat , Yahaya Muhammad
Published: November 2010

This paper reports a study on fluorescence sensing properties of cadmium telluride (CdTe) quantum dots (QDs) film under exposure of volatile organic compounds; ethanol, 2-propanol and acetone. The high luminescence QDs were synthesized using a wet-chemical process. CdTe QDs film was deposited onto the surface of fiber optic probe by drop-casting method. The fluorescence properties of the film were studied by observing the change of photoluminescence (PL) spectra of the films in nitrogen (N2) and after exposing in organic vapors. It was observed that the PL of the film was quenched by the presence of the organic vapors. The amount and the rate of quenching are depended on the kind of the organic vapors
Two Synchronized Operating Modes of Femtosecond and Picosecond Pulses in a Dual-Wavelength Laser
Authors: Zhu Chang Jun , He Jun Fang , Zhai Xue Jun , Xue Bing , Zhang Chong Hui
Published: November 2010

Two synchronized operating modes of femtosecond and picosecond pulses, cross mode-locking and multi-pulse operating, are presented in a two-beam-pumped dual-wavelength Ti:sapphire laser. For the cross mode-locking mode, synchronized laser pulses of 37.5 fs and 0.891ps, with a timing jitter of 139 fs, are obtained in the femtosecond cavity and picosecond cavity, respectively. For the multi-pulse mode, pulses of 35 fs are obtained in the femtosecond cavity, whereas, multi-pulse mode appears in the picosecond cavity, with a pulse envelope width of 1.06 ps. The two operating modes can be switched from one to the other, dominated mainly by the mutual interaction between cross-phase modulation and self-amplitude modulation.
Photoluminescence of Pyrrole Oxidized in Hydrogen Peroixde
Authors: Ma Qing Lan , Zhai Bao Gai , Huang Yuan Ming
Published: November 2010

The optical absorption and photoluminescence (PL) of 5-(2-pyrrolyl)-2-pyrrolidinone were investigated with ultra-visible absorption spectroscopy and photoluminescence spectrscopy. Upon the 325 nm excitation from a helium-cadmium laser, strong blue PL was recorded for the 5-(2-pyrrolyl)-2-pyrrolidinone. The peak of the PL was located at about 425 nm (2.92 eV). The origin of the strong PL can be assigned to isolated carbonyl group.
Preparation and Characterization of Porous Silicon in HF-AgNO3 Solution
Authors: Yang Wen Bin , Wun Jun , He Fang Fang , Tang Xiao Hong , Zhou Yuan Lin
Published: November 2010

Porous silicon (PS) of uniform structure was prepared by electroless silver deposition on surface of silicon at near room temperature in HF-AgNO3 system solution. Morphology of PS was characterized by scanning electron microscopy. The results showed that the diameter of hole was 1-2μm and holes distributed regularly. The ethylene diamine tetra acetic acid (EDTA) was an important additive to control the etching rate of silicon, which is of great significance to research the mechanism of porous silicon formation. Furthermore, photoluminescence property of PS was characterized.
The Influences of Turbid Media on the Optical Property of Different Ultra Short Gauss Pulse
Authors: Zhao Man , Zhao Chang
Published: November 2010

Based on the diffusion approximation theory, when the laser pulse transmitting through the turbid media, its energy will be attenuated and the pulse shape will be changed by the scattering and absorption. In this paper, Mathematics equations of the ultra short Gauss laser pulse in different pulse width tp are given, the reflective pulses with the boundary condition of semi-infinite homogeneous media are discussed. We get the simulation results of reflective intensity and the reflective pulse shape of different tp based on the diffusion equation. From the results, we know that the ultra short Gauss laser pulse will be widened by the diffusive scattering. Besides, we find that the various medium parameters will influence the reflection of the Gauss laser pulse very differently. With the boundary condition of semi-infinite homogeneous media, the influence of the absorption, the scattering, and the anisotropy coefficient will be also changed by the different tp of ultra short Gauss laser pulse. All the conditions mentioned above have been investigated in the present paper. This study will be very useful for the measurement of optical properties of tissue.
Synthesis and Luminescence Properties of 1,10-Phenanthroline Terbium/Polyvinyl Alcohol Hybrid Functional Materials
Authors: Zhang Hua , Zhou Lei
Published: November 2010

A series of 1, 10-phenanthroline terbium/ polyvinyl alcohol hybrid materials with different coupling agent contents were prepared by sol-gel method. The morphology and photophysical properties were investigated. FT-IR was applied to characterize the structure of the obtained hybrid material, SEM and fluorescence spectra were applied to characterize the performance of the hybrid material. The result shows that the phase separation processes and the fluorescence quenching were avoided and the optical performance of hybrid materials were improved effectively.
The Study on Microstructural and Optical Properties of Nanocrystalline Germanium Films
Authors: Song Chao , Huang Rui
Published: November 2010

The germanium film and Ge/Si multilayer structure were fabricated by magnetron sputtering technique on silicon substrate at temperatures of 500°C. Raman scattering spectroscopy measurements reveal that the nanocrystalline Ge occurs in both kinds of samples. Furthermore, from the atomic force microscopy (AFM) results, it is found that the grain size as well as spatially ordering distribution of the nc-Ge can be modulated by the Ge/Si multilayer structure. The room temperature photoluminescence was also observed in the samples. However, compared with that from the nc-Ge film, the intensity of PL from the nc-Ge/a-Si multilayer film becomes weaker, which is attributed to its lower volume fraction of crystallized component.
Near-Infrared-to-Green Upconversion in Yb3+/Er3+ Co-Doped BaYF5 by Chemical Co-Precipitation Method
Authors: Du Hai Yan , Zhang Wei Hang , Sun Jia Yue
Published: November 2010

Barium yttrium fluorides ( BaYF5 ) co-doped with Er3+ and Yb3+ were synthesized by the chemical co-precipitation method and the structural and optical properties of solution-processed Er3+/Yb3+ co-doped BaYF5 were characterized. Intense visible emissions centered at around 523, 546 and 658 nm, originated from the transitions of 2H11/2 → 4I15/2, 4S3/2 → 4I15/2, and 4F9/2 → 4I15/2 of Er3+, respectively, have been observed in samples upon excitation with a 980nm laser diode, and the involved mechanisms have been explained.
Photoluminescence of Eu3+-Doped La2Mo2O9 Phosphors
Authors: Wang En Guo
Published: November 2010

Eu3+-doped La2Mo2O9 phosphor was fabricated by sold-state reaction method. The as-prepared samples were characterized by the application of X-ray diffraction (XRD), scanning electron microscopy (SEM), and emission spectra. The effect of the sintering temperature and doping amount of europium ion on the luminescent properties of La2Mo2O9:Eu3+ was investigated. The results show that the luminescent intensity will reach the strongest when the sintering temperature is equal to 1073 K. The Eu3+ doping amounts also have obvious effect on the luminescent properties.
Photoluminescence Characteristics of Silicon Oxynitride Films at Different Annealing Temperatures
Authors: Song Jie , Guo Yan Qing , Wang Xiang , Zhang Yi Xiong , Song Chao , Huang Rui
Published: November 2010

Silicon oxynitride films were deposited in very-high-frequency (40.68 MHz) plasma enhanced chemical vapor deposition (VHF-PECVD), and subsequently annealed between 400 and 1200°C in N2 ambient. The effect of annealing temperature on the PL characteristics of the samples was investigated. The experimental results reveal that a broad PL peak around 430 nm (2.88eV) appears in all of the samples. The maximum intensity of this broad PL peak was obtained in the sample annealed at 400°C. The PL characteristics of the annealed samples were discussed.
Effect of Ammoniating Temperature on Growth of GaN Nanowires with V as Intermediate Layer
Authors: Shi Feng , Yang Zhao Zhu , Xue Cheng Shan
Published: November 2010

GaN nanowires have been successfully grown on Si (111) substrates by magnetron sputtering through ammoniating Ga2O3/V thin films. The influence of ammoniating temperature on the growth of GaN nanowires was analyzed in particular. The results demonstrate that ammoniating temperature has great influence on the growth of GaN nanowires. GaN nanowires are single crystal GaN with a hexagonal wurtzite structure and high crystalline quality after ammoniation at 900 oC for 15 min, which are straight and smooth with uniform thickness along the spindle direction and high crystalline quality, 50 nm in diameter and several tens of microns in length with good emission properties, and the growth direction of the nanowire is along the preferred (002) plane. A clear red-shift of the band-gap emission has occurred. The growth mechanism is also discussed briefly.
Synthesis and Electrochromic Properties of Novel Oligothiophene Derivatives
Authors: Guan Li , Wang Juan , La Ming , Zhong Yi Ping , Liu Ping , Deng Wen Ji
Published: November 2010

In order to develop novel electrochromic materials, 2,3′:4′,2″-terthiophene (I3T), 5,5′-biformyl- 2,2′:5′,2″:5″,2″′-quaterthiophene (4T-2CHO), and 2,5-(5′-cyano)thienyl-3,4-thienyl-t- hiophene (XT-2CN) were synthesized, and their electrochromic properties were studied. It was found that I3T, 4T-2CHO and XT-2CN as solid films showed reversible, clear color changes on electrochemical doping and dedoping. These oligothiophene derivatives constitute a new class of potential electrochromic materials.
Preparation and Photoluminescence of Ca3(VO4)2: Eu3+, Bi3+ Phosphor Powder
Authors: Li Yu Zhong , Zhou Xiao Chun
Published: November 2010

Ca3(VO4)2: Eu3+, Bi3+ phosphor powders were prepared by the combustion synthesis or the solid state reaction at room temperature, respectively. The phase composition, morphology and photo-luminescence of the Ca3(VO4)2: Eu3+, Bi3+ phosphors were investigated by X-ray diffraction, scanning electron microscope, and spectrophotometry, respectively. The results show that the Ca3(VO4)2: Eu3+, Bi3+ powder prepared by the combustion synthesis is claviform, while the Ca3(VO4)2: Eu3+, Bi3+ powder directly obtained by the solid state reaction at room temperature is orbicular. The discrepancy in emission is attributed to the variation in the Eu3+ morphology of in powders.
Second Harmonic Generation Properties of RbTiOPO4 Crystal
Authors: Zhao Yong Guang , Wang Zheng Ping , Sun Xun , Yu Hao Hai , Guo Lei , Chen Li Juan , Zhuang Shi Dong , Xu Xin Guang
Published: November 2010

For RbTiOPO4 (RTP) crystal, the second harmonic generation (SHG) properties of 1064nm are discussed, including phase matching (PM) direction, effective nonlinear optical coefficient (deff), walk-off angle, and angular acceptance. For the frequency doubling of nano-second and pico-second Nd:YAG laser, the conversion efficiency of RTP crystal can reach 51 % and 57 %, respectively. The laser damage threshold of RTP crystal is measured.
Preparation and Characterization of ZnS/ZnO Compound Grown on Porous Silicon Substrate Using CVD Method
Authors: Zhong Fu Ru , Lv Xiao Yi , Jia Zhen Hong
Published: November 2010

We have investigated the morphology and photoluminescence (PL) of Zinc Oxide (ZnO) and Zinc sulphide (ZnS) compound grown on porous silicon at room temperature. Under different excitation wavelengths (320 nm, 340nm, 370 nm), the photoluminescence (PL) spectra of PS-ZnS-ZnO composites were different, and at 550nm there is a strong photoluminescence peak. Energy dispersive spectroscopy (EDS) has been carried out to evaluate the existing of ZnO/ZnS compound. In addition, the scanning electron microscopy (SEM) observation shows that the morphology of the PS-ZnS-ZnO composites was well grown on porous silicon.
Optical and Structural Properties of TiO2 Films Deposited from Different Titanium Oxide Materials by Electron Beam
Authors: Wang Feng Xiang , Hwangbo Chang Kwon , Jung Bu Yong , Qi Jun He
Published: November 2010

TiO2 thin films were deposited from Ti2¬O3, TiO2 and Ti3O5 source materials by e-beam. The refractive index and extinction coefficient of the films in the visible and near infrared（IR） region were measured. The structural and chemical properties of the films were investigated by x-ray diffraction (XRD), atomic force microscopy (AFM) and x-ray photoelectron spectroscopy (XPS). XRD measurements revealed that all the deposited films were amorphous. XPS analysis showed the films were stoichiometric TiO2. The AFM investigation confirmed that the surface roughness of the films was dependent on the deposition conditions.
Photoluminescence Spectra of PbSe Quantum Dots with Different Reaction Time and Temperature
Authors: Sun Xiao Lan , Dong Yan Hua , Li Chao , Liu Xiao Hong
Published: November 2010

The size of quantum dots (QDs), their shape, and ordered arrays have significant impact on electrical and optical properties of the QDs. We synthesized near-infrared-emitting PbSe QDs via an oil phase method in a noncoordinating solvent. Transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy were used to characterize the samples. Sizes of the QDs were accurately controlled from 4.2 nm to 10.2 nm through control of the reaction time as well as the growth temperature. The PL spectra showed strong size dependence, which is large red shift with increasing size of the QDs.
Effects of O2 Ambient on Structural, Optical and Electrical Properties of Hafnium Oxide Thin Films Prepared by E-Beam Evaporation
Authors: Yang Chen , Chen Zhi Ming , Xi Ying Xue , Lin Tao
Published: November 2010

In this paper, thin HfO2 films were grown by using E-beam evaporation technique in vacuum and O2 ambient, respectively. Effects of O2 ambient on structural, optical and electrical properties of the HfO2 films were investigated by deploying x-ray photoelectron spectroscopy, ultraviolet visible spectroscopy, I-V and C-V characteristics. Results show that the O2 ambient deposited HfO2 films exhibited excellent structural, optical and electrical properties as compared with vacuum ambient HfO2 films, which especially performs a low content of metal Hf, a high transmittance, a low leakage current and a high dielectric constant.
Uncooled Infrared Bolometer Arrays with α-Si and Metal Films
Authors: Liu Huan , Wang Shan Shan , Cai Chang Long , Zhou Shun
Published: November 2010

A bolometer with stress equilibrium based on α-Si and metal films is proposed in this paper. The sensitive and support material α-Si films are prepared by plasma enhanced chemical vapor deposition（PECVD）, their stress and deposition rate are studied, and the technological parameter of the low stress and higher temperature coefficient of resistance (TCR) α-Si film are obtained. The result shows that the stress of the α-Si films can be adjusted between positive and negative. Pt films are deposited by electron-beam evaporating equipment. Their square resistance, TCR and stress are tested by four point resistivity test system and film-stress interferometer. The result shows this material is a good heat-sensitive material, and at the same time it can balance the stress of α-Si film. Finally it is found that Pt film is in compressive stress state in the selected technological parameters, and α-Si thin film is in tensile stress state, so the stress of micro-bridge structure can be balanced by this method. In the final, 160×120 infrared micro-bridge array on the wafer and read out integrated circuit (ROIC) chip are successfully fabricated.
Luminescent Properties of Ca2-XBO3Cl:xDy3+ Phosphors for White Light-Emitting Diodes
Authors: Yang Qing Xuan , Fu Xiao Guang , Wang Xiao Jun
Published: November 2010

Novel single-phase Ca2-xBO3Cl:xDy3+ phosphors were synthesized at 900 oC in an activated carbon reducing atmosphere, and their luminescent properties were investigated by photoluminescence (PL) and photoluminescence excitation (PLE) spectra. The optimal doping concentration of Dy3+ ions is found to be x=0.03 mol, and the nature of resonance energy transfer for Dy3+ ions is also discussed. Generation of white-light excited by 390 near-ultraviolet (n-UV) light shows that all the investigated phosphors lie within white region and the colour coordinate of Ca1.95BO3Cl:0.05Dy3+ (0.272, 0.326) is closer to the equal-energy white light point, which is potentially a good candidate as an n-UV-converted phosphor for white light-emitting diodes (LEDs).
Investigation of Factors Induced the Non-Intrinsic Optical Properties for Water-Soluble CdSe Semiconductor Quantum Dots
Authors: Qiu Heng Kang , Shen Yue , Wang Lin Jun , Zhang Jian Cheng , Qin Kai Feng
Published: November 2010

For the purpose of investigating the factors induced the non-band-edge excitation optical properties of water-soluble CdSe semiconductor quantum dots (QDs), the initial molar ratio of Cd and Se(or Cd/Se), the temperature of crystal nucleation and growing, the time of the growth etc. are systematically studied in the fabricated process. The properties of the as-prepared nano-particles (NPs) have been characterized by ultraviolet-visible absorption spectra (UV-Vis), photoluminescence (PL) spectroscopy, X-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy (XPS). The measured results show that it is possible to exist surface trapping, impurities and other defect energy states in the products with the non-band-edge excitation PL properties, and all the characteristics are involved with the different synthetic routes and prepared techniques.
Impact Study of Substrate Materials on Wireless Sensor Node RF Performance
Authors: Zheng Li Qiang , Mathewson Alan , O'Flynn Brendan , Hayes Michael , O'Mathuna Cian
Published: November 2010

In this paper, the effect of the substrate on wireless sensor network (WSN) node’s RF performance is studied experimentally by using different substrate materials with different thickness. A six-layer FR4 substrate PCB WSN node is fabricated and compared with the original two-layer FR4 PCB node to show the impact of substrate material thickness. Also different substrate dielectric constants’ impacts are studied by the same method. All these demonstrators are modeling by RF circuit analysis method and simulated in the Ansoft Designer software. Simulation results match the experimental measurement. An optimization method based on simulation for WSN node design with different substrate is presented. This analysis, modeling, simulation and optimization procedure can be carried out on some novel substrate materials such as LTCC and LCP.
Intrinsic Carrier Concentration in Strained Si1-XGex/(101)Si
Authors: Song Jian Jun , Zhang He Ming , Hu Hui Yong , Dai Xian Ying , Xuan Rong Xi
Published: November 2010

The intrinsic carrier concentration is the important parameter for researching strained Si1-xGex materials properties and evaluating Si-based strained devices parameters. In this paper, at the beginning of analyzing the band structure of strained Si1-xGex/(101)Si, the dependence of its effective densities of states for the conduction and valence bands (Nc, Nv) and its intrinsic carrier concentration (ni) on Ge fraction (x) and temperature were obtained. The results show that ni increases significantly due to the effect of strain in strained Si1-xGex/(101)Si. Furthermore, Nc and Nv decrease with increasing Ge fraction (x). In addition, it is also found that as the temperature becomes higher, the increase in Nc and Nv occurs. The results can provide valuable references to the understanding on the Si-based strained device physics and its design.
Comparison of Bonding of Bulk PZT to Silicon by Intermediate Glass Layer and by Intermediate Au Layer
Authors: Sun Jian , Li Yi Gui , Liu Jing Quan , Yang Chun Sheng , He Dan Nong , Van Thanh Dau , Tanaka Katsuhiko , Sugiyama Susumu
Published: November 2010

As an energy conversion material, piezoelectric ceramic lead zirconate titanate (PZT) has been used in a wide range of areas. And a PZT wafer bonding with a silicon wafer technology is a promising method to fabricate micro-sensors and micro-actuators using well-established silicon machining techniques. In order to obtain the excellent piezoelectricity and suitable thickness from the bulk PZT, a method is presented. It is to bond a bulk PZT onto a silicon wafer via an intermediate layer. In this paper, two bonding methods are presented. One is to bond a bulk PZT with a silicon wafer by anodic bonding technique using a thin glass film as the intermediate layer. The other is to bond a bulk PZT with a silicon wafer by eutectic bonding using a thin gold film as the intermediate layer. The glass film is 2µm in thickness, deposited by sputtered method. Anodic bonding conditions are: 0.8MPa in pressure, 500 oC in temperature, 250V in voltage and different bonding time. The bonding strength test shows that the maximum bond strength is 13.93 MPa when the bonding time was 60 min. It is void-free structure in the interface of the PZT-Glass-Si structure. The gold film is 1.6µm in thickness, deposited by evaporation method. The eutectic bonding conditions are: 0.8MPa in pressure, 500 oC in temperature, and different bonding time. The bond strength of the PZT-Au-Si structure was tested and the maximum value was 13.19 MPa when the bonding time was 60 min.
Switching Characters of SiCGe/SiC Heterojunction: An Optically Triggered Lateral Power Transistor with Charge Compensation Layer
Authors: Pu Hong Bin , Cao Lin , Chen Zhi Ming , Lin Tao , Zhou Shao Jiang
Published: November 2010

The switching character of SiCGe/SiC heterojunction phototransistors with charge-compensation technique has been simulated with commercial simulator MEDICI. The influences of light power density, wavelength and carrier lifetime on switching characters were studied. Simulation result shown that the devices are latch-free device and fall time is much longer than rise time. The increasing of light power density and wavelength cause shorter rise time and longer fall time unless reaches SiCGe absorption edge 520nm, trade-off must made between responsivity and switching speed when carrier lifetime is considered, the ratio of them gets it maximum values at minority carrier lifetime equal 90ns.
Analysis on the Characteristics of Transient Signal Transmission Based on GaAs Materials
Authors: Liu Wei , Lan Tian
Published: November 2010

The GaAs photoconductive switch is an important device in the measurement of the signal of ultra high-speed. In this paper, the transmission model of transient signals on GaAs photoconductive material is given, and the experimental system of near-field detection is set up. It is gotten that the full width half magnitude of signal is about 2ps. Based on the testing result of delay-time-modulation method, the relationship between signal amplitude and the form of connection mode is analyzed and discussed. It is shown that the coupling of capacity is important to acquire the transient signal.
An Interesting Result of Dielectric Property for Novel Polyimides with Fluorene Groups
Authors: Yuan Yuan , Xie Bing , Wang Yu
Published: November 2010

A series of polyimide thin films were prepared successfully based on bis[3,5-dimethyl-4- (4-aminophenoxy)phenyl]methane （BDAPM）, 9,9-bis（4-（4-aminophenoxy）phenyl）fluorene (BAOFL) and different dianhydrides. And an interesting result of dielectric property for polyimide thin films was found that the polyimide thin film prepared with 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) exhibited high dielectric constants of 5.7 at 1MHz. Conversely, the other polyimides possessing fluorene groups showed low dielectric constants. The structures and the mechanical properties of polyimide films also proved the reason for results of dielectric properties.
The Effect of the Coating Layer and the Doped Ion Concentration on the Dielectric Properties of SiO2-PANI Electrorheological Fluid
Authors: Zhou Wei , Liang Seng , Sun Yue Mei
Published: November 2010

The silicon dioxide particles are coated by polyaniline (PANI) under low temperature, and the doped ion concentration in PANI was adjusted by ammonia with different pH. The dielectric properties of PANI/SiO2 eletrorheological (ER) fluids are measured by impedance analyzer. The results indicated that the dielectric increment and relaxation frequency of ER fluid were enhanced after surface modification of SiO2, which are positive to the ER effect. Moreover, the pH of ammonia can change the relaxation frequency of ER fluid, which can improve the response ability of ER fluid to electric field.
Codoping Effects and Electrical Properties in Sol-Gel Li-Al Doped Zinc Oxide
Authors: Nian Hong En , Kim Eui Jung , Zhou Yuan , Ren Xiu Feng , Pang Yu Na , Wang Hong Bin
Published: November 2010

Li and Al codoped ZnO (LAZO) thin films have been prepared by sol-gel method. The electrical and structural properties of the LAZO films have been investigated. X-ray diffraction (XRD) results showed that the prepared LAZO films had a polycrystalline hexagonal wurtzite structure. X-ray photoelectron spectrometer (XPS) measurements indicated that our sol-gel prepared films were of high purity and codoped with Li and Al evidenced by peaks centered at 74.1 and 55.6 eV. The resulting LAZO films were p-type, and had a low resistivity in the range of 10-3~100 Ωcm, and high carrier concentration in the range of 1014~1018 cm-3.
Template Synthesis of Activated Carbon for Supercapacitor
Authors: Wang Ren Qing , Fang Qin , Deng Mei Gen
Published: November 2010

Activated carbon was fabricated by using phenolic resin as carbon source, tween-80 as organic template, KOH as activator. The samples were analyzed by N2 adsorption, scanning electron microscopy (SEM). Cyclic voltammetry and galvanostatic charge-discharge were used to characterize the electrochemical performance of the samples. The results showed that specific surface area of the prepared sample was 1935.99 m2/g, pore size was mainly in the range of 1.0～4.0 nm and showed typical capacitance characteristics in cyclic voltammetry. At a current density of 15mA/cm2, a specific capacitance of 246.18F/g was achieved and the resistance was 1.11Ω. Supercapacitors based on the sample had low ESR and excellent power property.
Growth and Defects of Magneto-Optical YFeO3 Single Crystal
Authors: Shen Hui , Xu Jia Yue , Wu An Hua , Jin Min , Jiang Guo Jian
Published: November 2010

YFeO3 single crystal, as a novel magneto-optical material, has attracted much attention due to its remarkable properties of primary significance for technological applications. In this work, YFeO3 crystal was successfully grown by optical floating zone method. Some voids are observed in the polished surface. The voids are effectively decreased by denser feed rod. In the etching samples, hexagonal etch patterns, sub-grain boundary and concentric growth striations were observed by optical microscope and SEM. The formation mechanism of these defects was discussed, and effective measures to restrain these defects were also proposed.
Study on the Energy Structure of Amorphous Antireflection Er2O3 Films on Si(001) Substrates
Authors: Zhu Yan Yan , Fang Ze Bo , Ji Ting , Liu Yong Sheng
Published: November 2010

Er2O3 films were deposited on Si(001) substrates by radio frequency magnetron technique. X-ray photoelectron spectroscopy, x-ray diffraction and atomic force microscopy show the Er2O3 films obtained are stoichiometric, amorphous, and uniform. The electronic structure is studied which shows a large energy gap value of the Er2O3 film, indicating Er2O3 film could be a promising antireflection coating for solar cells.
Electrical Properties of Hydrogen Terminated P-Type Diamond Film
Authors: Xia Fu Yuan , Wang Lin Jun , Huang Jian , Tang Ke , Zhang Ji Jun , Shi Wei Min
Published: November 2010

Undoped high quality polycrystalline diamond films were grown by the microwave plasma chemical vapor deposition (MPCVD) method. The effects of hydrogen plasma treatment and vacuum annealing process on the p-type behavior of diamond films were investigated by the Hall effect method. The sheet carrier concentration increased and the sheet resistivity decreased with the treating time of hydrogen plasma and a stable value was achieved finally. After annealing the samples in vacuum at temperature above 600 °C, the sheet carrier concentration dropped dramatically. The origin of this hydrogen terminated p-type conductive layers is also discussed.
Influence of ZnO-B2O3-Na2O Glass on Microwave Dielectric Properties of Ca[(Li1/3Nb2/3)0.8Sn0.2]O3−δ−0.1TiO2 Ceramics
Authors: Xiong Gang
Published: November 2010

The effects of ZnO-B2O3-Na2O(ZBN) glass on the sinterability and microwave dielectric properties of Ca[(Li1/3Nb2/3)0.8Sn0.2]O3−δ−0.1TiO2 (CLNS−0.1TiO2) ceramics were investigated . ZBN glass doping can effectively reduce sintering temperatue by 100~150°C. The temperature coefficient of resonator frequency τf increased with an increase of ZBN glass content and sintering temperatue. When ZBN glass of 3wt% were added, the optimum microwave dielectric properties: εr =28.8,Qf =10960GHz and τf = − 7.5×10−6/°C were obtained at the sintering temperature of 1050°C.