超晶格量子阱的沟道效应与光学双稳态效应

构造了一种高阶非线性"抛物线"量子阱,并提出了一种获得光学双稳态的新概念.指出了只需在超晶格量子阱的两端加上一个直流电场和交变电场,便可用它作为光学双稳态器件.引入高阶非线性"抛物线"势,并考虑到粒子运动阻尼和外场作用,在经典力学框架内和弱偏置下,粒子运动方程化为了具有硬弹簧特性的Duffing方程.用摄动法找到了系统的近似解,并分析了共振线附近粒子的运动行为与系统的稳定性.结果表明,粒子的振幅平方与外场振幅平方的关系曲线出现了后弯现象,正是这个后弯现象决定了系统存在双稳态,也正是这个双稳态决定了具有四阶非线性抛物线势阱的超晶格量子阱可望作为光子或光电子技术中新的记忆元件或存储元件.     

小振幅近似与形变超晶格系统的动力学稳定性

假设超晶格的"锯齿形"沟道对粒子的作用可等效为形状相似的周期调制,引入正弦平方势,并在小振幅近似下,把粒子运动方程化为具有硬弹簧特性的Duffing方程.利用多尺度方法分析了共振线附近的粒子运动行为,讨论了系统的主共振、子共振和超共振.计算了超晶格"锯齿形"沟道的临界斜率与系统参数之间的关系,为能带工程或超晶格光磁电效应的进一步研究提供了理论分析.     

小振幅近似与形变超晶格系统的动力学稳定性

假设超晶格的"锯齿形"沟道对粒子的作用可等效为形状相似的周期调制,引入正弦平方势,并在小振幅近似下,把粒子运动方程化为具有硬弹簧特性的Duffing方程.利用多尺度方法分析了共振线附近的粒子运动行为,讨论了系统的主共振、子共振和超共振.计算了超晶格"锯齿形"沟道的临界斜率与系统参数之间的关系,为能带工程或超晶格光磁电效应的进一步研究提供了理论分析.     

掺杂超晶格量子阱作为光学双稳态器件的可能性

引入正弦平方势来描述掺杂超晶格由于交替掺杂引起的导带周期性调制,并提出了一种获得光学双稳态的新概念.指出了只须在超晶格量子阱的两端加上一个直流电场和交变电场,便可以用它作为光学双稳态器件.在经典力学框架内和小振幅近似下,考虑到运动阻尼和外场作用,粒子运动方程化为了具有硬弹簧特性的Duffing方程.用摄动法找到了系统的近似解,并分析了共振线附近粒子的运动行为与系统的稳定性.结果表明,粒子的振幅平方与外场振幅平方的关系曲线出现了后弯现象,正是这个后弯现象决定了系统存在双稳态,也正是这个双稳态效应决定了掺杂超晶格可望作为光子或光电子技术中新的记忆元件或存储元件.     

双曲正割平方势与量子阱的电子跃迁

引入了双曲正割平方势来描述超晶格量子阱中的电子运动, 利用这个相互作用势把电子的Schrdinger方程化为了超几何方程, 并以Ga1-xAlxAs/GaAs/Ga1-xAlxAs量子阱为例计算了电子的带间跃迁.结果表明,阱内的能级数目和跃迁能量与系统参数有关.于是,可望通过对势阱参数的控制来得到不同光电特性的量子阱材料.     

形变超晶格的位错模型与粒子的退道效应

引入位错模型讨论粒子的退道效应.把超晶格的沟道偏折等效为位错引起的沟道弯曲,并对刃型位错的退道行为作了具体分析.利用正弦平方势,把粒子运动方程化为具有外力矩的摆方程,用能量法分析了系统的相平面特征,导出了系统的退道系数.     

形变超晶格的位错模型与粒子的退道效应

引入位错模型讨论粒子的退道效应.把超晶格的沟道偏折等效为位错引起的沟道弯曲,并对刃型位错的退道行为作了具体分析.利用正弦平方势,把粒子运动方程化为具有外力矩的摆方程,用能量法分析了系统的相平面特征,导出了系统的退道系数.     

周期弯曲晶体的摆动场辐射作为短波长激光的可能性

指出了用传统方法把自由电子激光(FEL)推向更短波长将在技术上遇到严重挑战,并试图寻找新的光源.在周期弯曲晶体中作沟道运动的粒子,在沟道辐射的同时,还将不断产生摆动场辐射.在摆动场轨道曲率最大或最小处,摆动场辐射与粒子束平行,情况与自由电子激光类似.在摆动场轨道曲率相继最大(或最小)处产生的光子是受激的,且频率比常规自由电子激光高得多.在简谐近似下,描述了沟道辐射和摆动场辐射频率与频谱分布,讨论了沟道辐射和摆动场辐射之间的关系,分析了利用晶体摆动场辐射作为X-激光或γ-激光的可能性.     

非对称量子阱与系统的本征值和本征函数

利用薄膜生长技术,通过控制材料的厚度来调整阱宽,控制组分来调整阱深,得到了不同光电特性的超晶格半导体材料。为克服"方形"势阱过于简单和理想的缺点,引入非对称相互作用势来描述组分超晶格量子阱。在量子力学框架内,把电子的Schrodinger方程转化为超几何方程,用系统参数和超几何函数严格地求解了电子的本征值和本征函数,并以Ga1-xAlxAs-GaAs-Ga1-xAlxAs量子阱为例计算了电子的带内跃迁。结果表明,阱内的能级数目和跃迁能量与系统参数有关,适当调节参数可得到不同光电性能的超晶格量子阱。     

正切平方势与量子阱的带内跃迁和带间跃迁

引入了新的正切平方势来描述量子阱中的电子和空穴运动行为.在量子力学框架内,把粒子的Schr(o)dinger方程化为了超几何方程,并用系统参数和超几何函数严格地求解了粒子的本征值和本征函数,并以Ga1-xAlxAs/GaAs/Ga1-xAlxAs量子阱为例计算了电子和空穴的带内跃迁和带间跃迁.结果表明,电子和空穴在量子阱中的能量是量子化的,而阱内的能级数目和跃迁能量与系统参数有关.于是,可望通过对势阱参数的控制来得到不同光电特性的量子阱材料.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

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.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.