Hg_(1-x)Cd_xTe混晶中光学声子与电子的相互作用

本文用双格点模型描写Hg_(1-x)Cd_xTe 混晶的双模式光学振动,计算了T=77K时长波TO和LO声子的频率,理论值与实验值符合较好.引入双模式的Callen有效电荷,导出了Hg_(1-x)CdxTe 混晶中光学声子与电子相互作用的矩阵元.对于n型Hg_(?)Cd_(0.2)Te,计算了光学声子散射对自由载流子吸收系数的贡献(T=90K,λ=20μm),并与声学声子散射、电离杂质散射和无序散射进行了比较,结果表明光学声子散射是主要散射机构.     

用红外光吸收方法测定Hg_(1-x)Cd_xTe中电离杂质浓度和微沉淀物

由于动量守恒和能量守恒的要求,固体中自由载流子的光吸收过程总是伴随着声子或电离杂质散射过程。声子和电离杂质散射的强度很大程度上决定了自由载流子吸收系数。对于像Hg_(1-x)Cd_xTe这样的极性混晶半导体,采用唐文国的双模Callen有效电荷就可以计算出光学声子的散射强度,对于给定的样品,它仅和温度有关。声学声子和无序散射都微乎     

简并Hg_(1-x)Cd_xTe半导体的费密能级和Burstein-Moss效应(详细摘要)

本文讨论了Hg_(1-x)Cd_xTe窄禁带半导体在费密能级筒并情况下,本征载流子浓度计算公式的应用,并计及导带电子浓度的非抛物带修正因子,计算了简并Hg_(1-x)Cd_xTe半导体的费密能级。本文还在77～300K温度范围内测量了组份为x=0.165、0.170、0.194的Hg_(1-x)Cd_xTe薄样品的本征吸收光谱,观察到明显的Burstein-Moss移动。实验所得光学禁带宽度与费密能级计算结果一致。     

Hg_(1-x)Mn_xTe:红外探测器材料的一种新的侯选者

美国印第安纳州普杜大学物理系J.K.Furdyna在《SPIE》Vol.409(1983)上介绍一种新型材料Hg_(1-x)Mn_xTe,并将它与大家熟知并公认为目前最有前途的材料Hg_(1-x)Cd_xTe相比较。Hg_(1-x)Mn_xTe与Hg_(1-x)Cd_xTe这两种半导体材料有许多相似之处。在材料结构和晶体特性方面,Hg_(1-x)Mn_xTe也是一种优质的闪锌矿结构晶体,生长方法亦类似,只是Hg_(1-x)Mn_xTe的     

Hg_(1-x)Cd_xTe的纵向负磁阻研究

有关半导体的纵向负磁阻的现象在InSb等材料中有过研究,而对Hg_(1-x)Cd_xTe而言,所见的报道却很少。为了进一步评价材料的电学性质,探讨其散射机理,有必要对Hg_(1-x)Cd_xTe材料进行这方面的工作。我们对x=0.13～0.20的不同浓度的N-Hg_(1-x)Cd_xTe样品在SdH区及量子极限区观察到了由电离杂质散射引起的纵向负磁阻,其特性表现如下:     

未掺杂Hg_(1-x)Cd_xTe中杂质的鉴别和研究

引言当x值大于0.15时,Hg_(1-x)Cd_xTe材料为一种本征半导体。由于禁带宽度随组分x连续变化,故能设计出在1～14微米波长内具有理想性能的Hg_(1-x)Cd_xTe探测器。尽管这种合金系统具有接近本征的载流子浓度,然     

非抛物型能带半导体Hg_(1-x)Cd_xTe的本征载流子浓度

本文利用Kane的非抛物型能带模型及费密-狄拉克统计推得Hg_(1-x)Cd_xTe的本征载流子浓度公式为n_i=(1 3.25KT/Eg)9.56(10~(14))E_g~(3/2)T~(3/2) [1 1.9E_g~(3/4)exp(Eg/2kT)]~(-1), 该式适用于x=0.17～0.37,T≤300K范围,式中Eg(eV)=-0.295 1.87x-0.28x~2 (6-14x 3x~2)(10~(-4))T 0.35x~4。本文还测量了不同组份Hg_(1-x)CdxTe样品(x=0.19～0.251)在77K～300K温度范围的本征载流子浓度。将上述公式的计算结果与本文实验结果及其他作者实验结果相比较表明,该式在x=0.19～0.29,T=77～300K范围与实验符合很好。     

用红外光吸收法测定Hg_(1-x)Cd_xTe组分

在室温下测量了组分x=0.170～0.443的Hg_(1-x)Cd_xTe薄样品的本征吸收光谱,并采用参考文献[4][5]中的方法确定其禁带宽度,发现与禁带宽度相当的能量处的吸收系数为α(E_g,300K)=500 5600x。把该式作为用红外光吸收法测定Hg_(1-x)Cd_xTe组分的工作曲线,先测出未知组分的Hg_(1-x)Cd_xTe厚样品的吸收边,并延长到α(E_g,300K)处,得到E_g(300K)后,即可求得待测组分:     

用红外光吸收法测定Hg_(1-x)Cd_xTe的组分

本文用测量本征吸收光谱的方法,确定Hg_(1-x)Cd_xTe的禁带宽度Eg值,再根据Eg与x的关系来确定x值。在Hg_(1-x)Cd_xTe的本征吸收光谱上,Eg能量值出现在陡峭的指数吸收边和平坦的本征吸收带交界区域。利用本征吸收光谱确定Eg,需要对Hg_(1-x)Cd_xTe薄样品进行测量,样品厚度一般为10μm左右。我们用PE983红外分光光度计在室温下测量了七个已知组份的     

Hg_(1-x)Cd_xTe光学声子双模行为的物理本质

对于Hg_(1-x)Cd_xTe中的声子,迄今已知的特点是其光学声子有双模行为。本文提出一种物理图象,分析讨论这种双模行为的物理本质,由此得到一种计算Hg_(1-x)Cd_xTe声子谱的可能方法。本文分析的出发点是把Hg_(1-x)Cd_xTe三元合金看成具有0～25%替位杂质的二元晶体。替位杂质最多为25%(x=0.5时),最少为零(x=0或1时)。为分析问题方便起见,此     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

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.