RF—HFCVD生长高质量纳米金刚石薄膜

采用射频等离子体增强的热丝化学气相沉积 (RF HFCVD)技术在石英玻璃衬底上制备了高质量的纳米金刚石薄膜 .研究了衬底温度、反应气压及射频功率对金刚石膜的结晶习性和光学性质的影响 ,其最佳值分别为70 0℃、2× 133Pa和 2 0 0W .在该条件下金刚石成核密度达 10 11cm-2 ,经 1h生长即获得连续薄膜 ,其平均晶粒尺寸为 2 5nm ,表面粗糙度仅为 5 5 ,在近红外区域 (80 0nm处 )的光透过率达 90 % .     

微波等离子体化学气相沉积超纳米晶金刚石膜研究

超纳米晶金刚石(UNCD)在短毫米波特别是太赫兹真空器件输能窗中具有潜在的应用价值。本文介绍了UNCD膜的制备工艺和性能表征。利用微波等离子体化学气相沉积法在一种贫氢、富氩的反应气体中合成UNCD膜。扫描电子显微镜分析表明,合成的UNCD膜表面光滑平整,晶粒为纳米尺度,断面结构致密。X射线衍射分析显示,超纳米晶金刚石薄膜主要是以(220)取向为主的多晶体结构,计算得到的平均晶粒尺寸为10nm。拉曼光谱分析呈现出典型的超纳米晶金刚石特性,膜中存在一定的sp2相。UNCD的光学透过率测试显示:在波长≥4μm范围内,光学透过率≥60%。     

纳米光学金刚石薄膜的分析与改进

由于极其优良的热学和光学性能,纳米金刚石薄膜极有可能应用于背投电视的激光光学窗口。文章通过在热丝辅助化学气相沉积法中采用偏压增强成核(BEN-HFCVD) ,成功地在(100)硅衬底上制得了适于作为光学窗口的高质量的光学级纳米金刚石薄膜,采用的偏压为-30 V。通过表征制备的纳米金刚石薄膜,发现它具有光滑的表面,表面均方根粗糙度(RMS)约为10 nm,并且对自支撑纳米金刚石薄膜进行透射光谱分析得到其透射率达到了50 %。     

Au/SiO_2纳米复合薄膜的结构表征及光致发光特性

采用磁控溅射和退火技术制备出Au/SiO2纳米复合薄膜。利用扫描电子显微镜(SEM),X射线衍射(XRD)和原子力显微镜(AFM)对上述纳米复合薄膜进行了结构表征。实验结果表明,纳米复合薄膜的表面上均匀分布着直径在100～300nm的金纳米颗粒。金纳米颗粒的大小随着退火时间的增加而增大。用荧光光谱仪(PL)对薄膜的光致发光特性进行了研究。结果表明,在激发波长为325nm时,分别在525nm和560nm处出现两个发光峰;在激发波长为250nm时,在325nm处出现发光峰,这一发光峰可能与非晶SiO2的结构缺陷有关。     

热丝化学气相沉积法在CH4／H2混合气体中低温生长超薄纳米金刚石膜

用热丝化学气相沉积方法研究了低温(~550℃)和低反应气压(~7 Torr)下硅片上金刚石膜的成核和生长.成核过程中采用2.5%的CH4浓度,在经充分超声波预处理的硅片上获得了高达1.5×1011cm-2的成核密度.随CH4浓度的增加所成膜中的金刚石晶粒尺寸由亚微米转变到纳米级.成功合成了表面粗糙度小于4nm、超薄(厚度小于500nm)和晶粒尺寸小于50nm的纳米金刚石膜.膜与衬底结合牢固.膜从可见光至红外的光吸收系数小于2×104cm-1.用我们常规的HFCVD技术,在低温度和低压下可以生长出表面光滑超薄的纳米金刚石膜.     

Al掺杂ZnO薄膜的表面形貌和光学性质

用原子力显微镜、紫外-可见分光光度计和荧光光谱仪观察采用溶胶-凝胶法制备的Al掺杂ZnO薄膜的表面形貌、透射光谱和光致发光谱.结果表明,Al掺杂量为0.5at 9/6的ZnO薄膜经550℃退火处理后,粗糙度为1.817,Al掺杂量为1.0at%的ZnO薄膜经600℃退火处理后,粗糙度增大到4.625.样品在可见光范围内的平均透过率均大于80%.当激发波长为325 nm时,在397 nm(3.13 eV)附近出现紫外发光峰;当激发波长为360 nm时,在443 nm(2.80 eV)附近出现蓝色发光峰.探讨了样品的蓝光发光机制.     

液相法电沉积类金刚石薄膜的结构分析

采用脉冲直流电源,以甲醇有机溶液作为碳源,在低温(60 ℃～70 ℃)常压条件下,在(100)硅片上沉积了类金刚石薄膜.用扫描电镜、透射电镜、电子衍射谱和拉曼光谱表征了薄膜的表面形貌和结构.结果表明:类金刚石薄膜致密均匀,表面粗糙度小;Raman光谱在1 332 cm-1附近有一强峰,与金刚石的特征峰接近;电子衍射谱的分析结果表明薄膜中含有多晶金刚石和石墨碳相.     

PECVD法制备类金刚石薄膜结构和表面形貌分析

以CH4为碳源,Ar气为载气,采用等离子体增强化学气相沉积法(PECVD)在硅(100)衬底上制备了类金刚石(DLC)薄膜。利用拉曼(Raman)光谱仪与原子力显微镜(AFM)对其结构与表面形貌进行了表征。结果表明:所制备的DLC薄膜是含sp3和sp2混合键的非晶态碳膜,其表面均匀、光滑、致密;且随着射频功率的提高,薄膜的平均晶粒直径由8.0nm降为4.2nm,粗糙度由2.2nm减为0.9nm。     

低红外发射率TiO2/Ag/TiO2纳米多层膜研究

利用磁控溅射在玻璃衬底上制备了具有良好的光谱选择性透过率的TiO2/Ag/TiO2纳米多层膜.通过用X射线衍射、扫描电子显微镜、UV-VIS-NIR分光光度计、傅里叶红外光谱仪对样品进行表征,优化了薄膜的制备工艺,研究了多层膜的光学特性.结果表明,当Ag膜的厚度为12nm时,多层膜具有高的可见光透过率和优良的导电性能.样品在555nm波长处的透过率最高达93.5%,红外波段平均反射率为90%左右,8μm～14μm波段红外发射率ε＜0.2.Ag层厚度的增加使可见光高透过率波段变窄,透过率下降.内层及外层TiO2厚度的变化引起薄膜可见光透过峰的位置及强度发生变化,外层的影响高于内层.     

等离子平板显示中冷阴极纳米金刚石膜的制备

讨论大面积 4 cm×4 cm 纳米金刚石膜制备工艺.采用电子辅助-热丝化学气相沉积法(EA-HFCVD)在硅片上沉积纳米金刚石膜.生长过程中,预先加 6 安培偏流生长 1 小时,然后在 0.8 千帕条件下,无偏流生长 3 小时.原子力镜表征晶粒尺寸为 30 纳米.样品上任意三点采用原子力镜表征,表现出良好均匀性.采用偏振光椭圆率测量仪和分光计分别表征样品的折射率和透射率.红外波段透过率超过 50%.金刚石膜表面分别进行氢化和氧化处理.通过表征,氢化处理后膜比氧化处理后膜对应的γ值大,约为 0.45.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.