（AlxGa1—x）yIn1—yP Films an Its Optical Constants on the Surface

The optical parameters for three samples of intrinsic,doped Si and doped Mg（AlxGa1-x)yIn1-yP prepared by the MOCVD on GaAs substrate were measured by using ellipsometry and were calculated by the two-layer absorption film model.The results obtained were discussed.The grown rates and thickness of oxidic layer on the intrinsic（AlxGa1-x)yIn1-yP surface exposed in the atmosphere were studied.Alinear dependence of oxidic layer thickness on the time was obtained.     

Photoluminescence Spectra of Disordered and Ordered Ga 0.52 In 0.48 P

Temperature-dependence and excitation-intensity-dependence of photoluminescence spectra for both disordered and ordered Ga0.52 In0.48P are measured.The disordered sample is charactierized by its single pcak photoluminescence spectrum which is excitation-intensity.independent and has different activation energy at different temperature region.The ordered sample shows double peaks,the intensity of the high-energy peak has an anomalous increase firstly and quenches afterwards.The relative henomena are reasonably explained in terms of lattice ordering and orientation superlattice model.     

Surface Morphology and Photoluminescence of 1.3μm Wavelength In（Ga） As／GaAs Quantum Dots

Self-organized In0.5 Ga0.5As/GaAs quantum island structure emitting at 1.35 μm at room temperature has been successfully fabricated by molecular beam epitaxy(MBE) via cycled(InAs)1/(GaAs)1 monolayer deposition method.Photoluminescence(PL) measurement shows that very narrow PL linewidth of 19.2 meV at 300 K has been reached for the first time,indicating effective suppression of inhomogeneous broadening of optical emission from the In0.5Ga0.5As islands structure.Our results provide important information for optimizing the epitaxial structures of 1.3μm wavelength quantum dot （QD） devices.     

Comparison of GexSi1—x Grown by UHV／CVD from Si2H6／GeH4 and SiH4／GeH4

Using double crystal X-rays diffraction (DCXRD) and atomic force microscopy (AFM), the results of Ge x Si 1- x grown by UHV/CVD from Si 2H 6 and SiH 4 are analyzed and compared. Adsorbates can migrate to the energy-favoring position due to the slow growth rate from SiH 4. In this case, a Si buffer that isolates the effect of substrate on epilayer could not be grown, which results in a pit penetrating into epilayer and buffer. The FWHM is 0.055° in DCXRD from SiH 4. The presence of diffraction fringes is an indication of an excellent crystalline quality. The roughness of the surface is improved if grown by Si 2H 6; however, the crystal quality of the Ge x Si 1- x material became worse than that from SiH 4 due to much larger growth rate from Si 2H 6. The content of Ge is obtained from DCXRD, which indicates the growth rate from Si 2H 6 is largest, then GeH 4, and that from SiH 4 is least.     

Optical Fiber Displacement Sensor with Ultra—high Resolution

A low fineness fiber optic Fabry-Perot interferometric displacement sensor has been developed and tested.A 0.005 nm displacement resolution is obtained by using He-Ne laser with a high performance,photodetectors with low nois,low drift operational amplifiers,6-pole Butterworth filters and perfect digital signal processing circuits.     

Fiber Grating Ring Laser in All Optical Communication System

Erbium fiber grating ring laser(EFRL)witn an integrated travelling wave and low polarization mode noise is reported.Through modulated experiment of a successful 2.488Gb/s RZ data,it is shown that the EFRL is a promising alternative to DFB lasers for high-speed transmission applications.     

Carrier Transport Properties in the Doped Micro—crystalline Silicon Films

Doped micro-crystalline silicon films are deposited at temperatures as low as 400 ℃ by the catalytic chemical vapor deposition method using a silane and hydrogen gas mixture. Electrical properties such as the carrier concentration and the Hall mobility are investigated for various measuring temperatures. It is found that the grains of micro-crystalline silicon are preferentially oriented along the (220) direction , and that the Hall mobility is larger than 8 cm 2·V -1 ·s -1 , the carrier concentration is about 1×10 17 cm -1 ～1×10 19 cm -3 at room temperature.     

New Fluoroptic Thermometer with Optical Fiber

A new optical fiber fluoroptic thermometer based on the temperature-fluoroptic characteristic of fluoroptic materials is presented.The ratio technique of intensities of fluorescent emission lines of certain rare earth phosphors is used,making the measurement of temperatures of the system to 0.5℃ precision.The characteristics of thermometer are discussed and the experiment results of temperature are given.     

Optical and Electrical Properties of Sensitized Polyaniline by Electrochemical Polymerization

To sensitize polyaniline with dyes by electrochemical polymerization,HClO4 is employed as the dopant and oxidant,and the polyaniline with differnet sensitive properties is synthesized.The effect of sensitized emeraldine salt on the absorption spectrum is discussed in details.The maximum conductivity of sensitized films reaches 1.22S/cm,and investigation on dye sensitizing of the polymer reveals that C.I.Direct Blue 71,C.I.Direct Blue 84,C.I.Direct Black 19 and CuPc-(COOH)4 may enhance the photoconductivity of polyaniline greatly.     

Influence on Conductivity of Polyparaphenylene by Chemical Doping and Ion Implantation

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MnQ2 ( Q =S ,Se,Te)and [Mn(en) 3]Te4StructuresandTheir

The solvo-thermal technique is used for the synthesis of Te 4 (I).The crystal structure has been determined by single crystal X-ray diffraction techniques.The crystal belongs to the monoclinic, space group p 2 1/ c with unit cell: a =0.846 1(1), b =1.565 3(2), c =1.426 9(2) nm, α =90°, β =91.37(1) (3)°, γ =90°, V =1.889 3(4) nm 3,and Z =4.The results show that the structure contains a linear chain Zintl anion, 2- and a complex cation, 2+ . Optical studies have been performed on the powder sample of I, suggesting that the compound is a semiconductor with a band gap of 0.73 eV. The semiconductor properties for MnQ 2(Q=S,Se,Te) and Te 4 have been discussed by molecular orbital theory.     

Mean Transverse Energy of Electrons Emitted from GaAs/GaAlAs Transmission Photocathode

A GaAs/GaAlAs transmission photocathode surface topography is examined with a scanning electron microscope(SEM)in the secondary emission mode.The contributions of photocathode surface topography to mean transverse energy of electrons emitted from the photocathode are calculated.Measurement is made of the variation of mean transverse emission energy with activating time during the course of activation.It is shown that the scattering of the photoelectrons in the Cs/O layer is the primary cause of the unexpectant high values of the mean transverse energy of electrons emitted from GaAs/GaAlAs photocathod.A method is proposed for the reduction of te mean transverse energy of electrons emitted from the photocathode.     

Preparation,Structure and DC Conductivity of Organic Semiconductor PANI—C4H6O6

A new organic semiconductor tartaric acid doped salt of emeraldine polyaniline(PANI-C4H6O6)has been obtained by the method of oxidative polymerization of monomeric aniline with ammonium persulfate in acidic solution.The structure was characterized by Fourier Transform Infrared technique(FTIR) and X-ray diffraction(XRD).The temperature dependence dc conductivity δdc(T)shows a semiconductor behavior and follows the quasi one dimensional variable range hopping(Q1D-VRH)model.Data on δdc(T) are also discussed.     

Growth of In-Rich In x Al1−x N Films on (0001) Sapphire by RF-MBE and their Properties

In-rich In _x Al_1−x N films (0.47 ≤ x ≤ 1) were grown directly on nitridated (0001) sapphire substrates without employing a buffer layer by radiofrequency molecular-beam epitaxy. Both photoluminescence peak energy and optical absorption-edge energy of the In _x Al_1−x N films decreased monotonically with increasing In composition, which was consistent with the recently reported InN bandgap energies of ∼0.7 eV. The bowing parameter of this alloy was estimated to lie between 2.9 eV and 6.2 eV. Substrate nitridation with lower temperature and longer period conditions not only reduced misoriented In _x Al_1−x N phases remarkably but also produced narrower tilt distribution in the c-axis-oriented In _x Al_1−x N matrix.     

热处理温度对掺钕钇铝石榴石陶瓷析晶的影响

采用氧化钕、氧化钇、硝酸铝、氨水以及柠檬酸作为原材料,以低温燃烧法(LCS)制备出纳米粉末材料。该方法解决了固相反应的高温合成及化学沉淀法的粉体团聚问题。通过热重-差热(TG-DTA)、X-射线粉末衍射(XRD)、傅里叶红外透射(FT-IR)和透射电镜(TEM)测试手段研究粉末的特性,采用谢莱方程(Scherrer)根据YAG(420)晶面的衍射曲线半峰宽数据计算出晶粒尺寸,详细研究陶瓷材料在不同热处理条件下的析晶情况。研究结果表明：YAG相的形成温度为850℃,在热处理过程中出现YAP中间相,于1050℃转变成纯YAG相,颗粒在不同的热处理条件下呈现不同的尺寸,在20～50nm范围变化。随着热处理温度的升高,平均晶粒尺寸增加,晶粒尺寸的标准偏差保持在2．0左右,晶格参数逐渐减小。晶粒主要以晶界扩散形式进行生长,晶格参数膨胀是由晶粒表面的排斥偶极距所造成的。