基于CuPc…C60的混合层异质结光伏器件性能研究

制备了基于CuPc…C60混合层异质结有机光伏器件,将其与CuPc-C60双层结构光伏器件进行对比研究。结果表明混合层结构器件性能得到改善,其开路电压、短路电流密度、填充因子和光电转换效率都有提高,分别从CuPc-C60双层结构器件的0.39V、1.92mA/cm2、0.36%、0.48依次提高到CuPc…C60混合层结构器件的0.48V、2.21mA/cm2、0.54%、0.51。根据整数电荷转移模型来分析光伏器件D/A界面及有机材料-ITO衬底界面特性,认为混合层异质结有机光伏器件给体材料HOMO与受体材料LUMO的能级差增加使得器件开路电压提高。混合层异质结有机光伏器件D/A界面面积增加和给体材料HOMO与受体材料LUMO的能级差增加都提高了激子的分离效率,所以器件的短路电流密度增加。     

低维磁性异质结复合材料的界面和电镜表征

低维磁性异质结复合材料因其界面处存在电荷、自旋、轨道和晶格等相互耦合作用而具有独特新颖的功能特性,被广泛应用于日常生活、民用工业和军事工业的各个领域。它新颖的综合物性与复合材料的微结构息息相关,这很大程度上取决于异质界面结构。因此,在纳米甚至原子尺度上深入探索低维异质结磁性复合材料的界面微观结构与宏观物性之间的构效关系,阐明低维异质结磁性复合材料的磁相互作用机制和磁性调控机理,能够为该类材料的设计开发、定向优化和实际应用提供实验和理论依据。本文简要介绍低维磁性异质结复合材料的制备、电镜表征及化学物理特性方面的研究进展,主要包括：铁磁/非磁性金属、非磁性金属/磁性氧化物、铁磁性/反铁磁性氧化物、铁磁性金属/碳材料、铁磁性氧化物/碳材料等。最后,对低维异质结磁性复合材料的未来发展趋势进行了展望,并在基础研究方面提出了一些建议。     

(8, 0)氮化硼/碳纳米管异质结的电子结构

异质结的能带结构是研究其构成器件工作机理的基础。建立了（8,0）氮化硼纳米管和碳纳米管构成的异质结的不同模型,其界面分别由碳氮键和碳硼键构成。采用基于密度泛函理论的第一性原理计算,对该模型进行了结构优化, 异质结的结构重构主要发生在其界面上;异质结的最低空轨道和最高占据轨道同时位于构成异质结的碳纳米管侧。在采用平均键能法计算了异质结的带阶后,绘制了（8,0）氮化硼/碳纳米管异质结的能带结构。     

基于P3HT/PCBM异质结界面太阳能电池的理论及实验研究

根据整数电荷转移(ICT)模型理论分析基于P3HT为给体PCBM为受体的异质结界面,认为不同等效功函数衬底和电荷传输状态产生不同D/A界面特性。采用增加P3HT缓冲层PCBM缓冲层的方法,制备不同复合层本体异质结结构光伏器件,研究活性膜内组分变化对器件开路电压和短路电流密度的影响。结果表明增加缓冲层使器件的短路电流密度明显提高,从3.96mA/cm2分别增加到4.51mA/cm2和4.70mA/cm2,但对开路电压影响不大。     

异质结构中载流子输运的二维自洽全能带系综蒙特卡罗模拟

本文展示了一个用于异质结构模拟的二维全能带系综蒙特卡罗 模拟器,它通过自洽求解二维泊松和波尔兹曼方程,同时处理 了载流子在两种不同半导体材料以及其其界面处的输运。本文 给出了该蒙特卡罗模拟器的内部结构,包括通过赝势方法计算 得到全能带结构、包含的不同散射机制和对载流子在两种不同 半导体材料边界输运的适当处理。作为验证,我们对两种不同 掺杂的Si-Ge异质结—p-p同型异质结和n-p异型异质结进行了 模拟,给出了其I-V特性以及电势和载流子浓度分布,这些结果 验证了我们的异质器件蒙特卡罗模拟器的有效性。     

二维层状材料异质结光电探测器研究进展（特邀）

自石墨烯时代以来,具有独特物理、化学和光电特性的二维层状材料(Two-Dimensional Layered Materials,2DLMs)得到了国内外科研人员的广泛关注。2DLMs因其种类的多样化与带隙的层数依赖性,光谱响应范围覆盖了紫外到红外辐射的极宽波段,具有应用于新一代光电探测器件的潜力。此外,2DLMs不受晶格匹配的限制,能以范德瓦尔斯力(Van der Waals,vdWs)与其他维度材料如体材料、纳米线和量子点等结合,制备得到性能独特且优异的复合结构器件。文中概述了几种应用在光电探测器领域的新型2DLMs异质结光电探测器的研究进展,主要包括基于二硒化钨(WSe₂)、黑砷磷(AsP)、三硫化铌(NbS₃)、二硒化钯(PbSe₂)等异质结光电探测器,这些异质结光电探测器在异质结器件结构设计与新型二维半导体工艺技术应用方面做出了创新,在器件增益、结整流比、响应速度与波长探测范围等多个重要器件性能方面获得了突破性的研究成果。同时,文中还简要分析了这类器件研究当前所面临的挑战,并对其未来的发展方向进行了展望。     

石墨烯异质结及其光电器件的研究进展

石墨烯是具有高迁移率、高热导率、高比表面积、高透过率及良好的机械强度等特性的二维材料,在光电子器件领域被广泛用作透明电极及电荷传输层等。但由于石墨烯是零带隙材料,为半金属性,限制了其在半导体光电子器件领域的应用。为更加切合半导体产业应用的要求,构建异质结已经成为相关领域实现应用的重要途径。国际上已有较多团队开展了石墨烯异质结相关研究,目前已有较多报道。本文从石墨烯的性质出发,讲述了石墨烯异质结的发展历程,制备方法,并从材料制备与器件结构的角度总结了基于石墨烯异质结光电子器件的研究进展。最后,对石墨烯异质结在光电子器件领域的发展进行了展望。     

平面掺杂异质结场效应管的二维电子气浓度和材料结构尺寸之间的关系

本文对场效应管所用材料的隔离层,δ调制掺杂层,势垒耗尽层等材料结构尺寸,异质结界面的二维电子气浓度,场效应管的夹断电压,沟道电流等以及它们之间的关系进行了计算分析,可作为材料和器件结构设计的依据．     

双异质结双平面掺杂HEMT器件的电荷控制模型

利用泊松方程以及异质结能带理论,通过费米能级-二维电子气浓度的线性近似,推导了基于双异质结双平面掺杂的HEMT器件的电荷控制模型.计算分析了沟道顶部和底部平面掺杂浓度,栅金属与顶部平面掺杂层距离等材料结构尺寸和阈值电压、二维电子气浓度的关系.该模型为优化和预测双平面掺杂HEMT器件性能提供了一个有效手段.     

双异质结双平面掺杂HEMT器件的电荷控制模型

利用泊松方程以及异质结能带理论 ,通过费米能级 -二维电子气浓度的线性近似 ,推导了基于双异质结双平面掺杂的 HEMT器件的电荷控制模型 .计算分析了沟道顶部和底部平面掺杂浓度 ,栅金属与顶部平面掺杂层距离等材料结构尺寸和阈值电压、二维电子气浓度的关系 .该模型为优化和预测双平面掺杂 HEMT器件性能提供了一个有效手段     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

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.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

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.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

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.     

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.