两步快退火改善InP（Fe）中MeV硅注入层的品质

２ＭｅＶ、（１～２）×１０１４ｃｍ－２硅离子注入ＳＩ－ＩｎＰ（Ｆｅ）造成负的（－３．４×１０－４～－２．９×１０－４）晶格应变，光快速退火的激活能为０．２６ｅＶ。８８０℃／１０ｓ退火可得到１００％的施主激活。间断两步退火（３７５℃／３０ｓ＋８８０℃／１０ｓ）使注入层单晶恢复完全，较大程度（２０％～３５％）地改善了载流子的迁移率。四能量叠加注入已能在０．５～３．０μｍ的深度区域形成满足某些器件要求的低电阻（７．５Ω）高浓度［（２～３）×１０１８ｃｍ－３］的ｎ型导电层。     

有机多层白光发光二极管

以四苯基二胺衍生物(TPD)为空穴传输材料,以蓝光染料酚基吡啶铍(BePP2)、黄光染料红荧烯(Rubrene)、绿光染料8-羟基喹啉铝(Alq3)分别为蓝、绿、红三基色染料,采用多层结构制备了有机多层白光发光二极管.该白光器件的色坐标为( 0.33, 0.36)(在7V下),接近等能点白光( 0.33, 0.33);该器件在17V下的亮度可以达到3000cd/m2,流明效率为 0.3 lm/w,是目前报道的比较好的结果.     

Si基Ge0.85Si0.15异质光电二极管

采用低温生长缓冲层,高温生长ＧｅＳｉ外延层的方法在ｎ型Ｓｉ衬底上外延生长（ｉ）Ｇｅ０．８５Ｓｉ０．１５－（ｐ）Ｓｉ层,以此材料作为吸收区制备成ＧｅＳｉ／Ｓｉ异质结ｐｉｎ台面光电二极管。其波长范围为０．７－１．５５μｍ,峰值波长位于１．０６μｍ,暗电流密度低达０．０３３μＡ／ｍｍ＾２（－２Ｖ）,在１．０６μｍ和１．３μｍ处的响应度分别为１．８Ａ／Ｗ（－２Ｖ）和０．０６６Ａ／Ｗ（－Ｖ）。     

Eu3+配合物红色有机电致发光器件

合成了一种新型的Ｅｕ＾３＋配合物－Ｅｕ（ＢＡ）２（ＭＡＡ）（Ｐｈｅｎ）,并将其作为红光发射材料制备了结构为Ｇｌａｓｓ／ＩＴＯ／Ｅｕ（ＢＡ）２（ＭＡＡ）（Ｐｈｅｎ）／Ａ１ｒ的有机电致发光薄膜器件。这种材料具有很强的荧光和很好的单色性且比较强的电致发光。器件的开戾电压为１２Ｖ。在电压为２６Ｖ的正向驱动下,器件的亮度为１５ｃｄ／ｍ＾２,发光效率为０．２５１ｍ／Ｗ。结合测量粉末、薄膜状态下的荧光光谱、激发     

光泵浦的InGaN垂直腔面发射激光器产生蓝色光

日本东京大学及德国维尔茨堡大学的研究人员报道了在室温下一个二维的光泵浦的垂直腔面发射激光器（ＶＣＳＥＬ）获得了蓝色激光（３９０ｕｒｎ）。这种器件的阵列可以显著缩短在高密度光学存储器中的读取时间。阵列中的每一个ＩｎＧａＮＶＣＳＥＬ直径为１８Ｐｍ,器件以２２Ｐｍ的间隔划分。在３６７ｕｒｎ处由一个重复频率３Ｈ。的ＮＺ激光泵浦的染料激光器来对ＶＣＳＥＬ进行泵浦。ＶＣＳＥＬ的发射门值是在１０ｍＪ／Ｃｍ’的泵浦能量或２～４ｘ１０‘’ｃｍ’载流子密度下产生。该器件是在以蓝宝石衬底的多层结构上做出的。在分布着反…     

掺杂聚合物薄膜黄绿发光二极管

在具有电致发光的有机聚合物薄膜ｐｏｌｙ(２－ｍｅｔｈｙｏｘｙ－５－ｅｔｈｙｌｏｘｙ)－４－ｄｉ－(２－ｍｅｔｈｙｏｘｙ－５－ｏｃｔａｏｘｙ)－ｐｈｅｎｙｌｏｎｅ－ｖｉｎｙｌｅｎｅ(简称 ＭＥＭＯ－ＰＰＶ)中掺入一种高荧光量子效率的染料罗丹明６Ｇ(Ｒ６Ｇ),用旋转涂敷的方法获得了发光层,同时将其作为空穴传输层,以８－羟基＠$铝(８－Ａｌｑ３)作为电子传输层,得到了多层有机发光二极管ＩＴＯ/ＰＰＶ:Ｒ６Ｇ/Ａｌｑ３/Ａｌ．该器件峰值波长为５５０ｎｍ,发黄绿光．研究结果表明:不同掺杂浓度对器件发光光谱产生较大影响;通过掺杂,可显著提高器件的稳定性．在１８Ｖ下,器件的亮度达到３６００ｃｄ/ｍ２,外量子效率达３．２%．     

Ge_xSi_(1-x)/Si应变超晶格PIN探测器的研制

本文对ＧｅｘＳｉ１－ｘ／Ｓｉ应变超晶格ＰＩＮ探测器进行了分析和设计（其中ｘ＝０．６），并制作出了相应的器件．对典型器件的测试结果表明，在１．３μｍ光照下，反偏电压为－５Ｖ时，光响应电流为２．６μＡ，暗电流为４００ｎＡ，探测灵敏度为０．１５３μＡ／μＷ．最大总量子效率为１４．２％．     

掺杂聚合物蓝绿发光二极管

本文报道了用有机染料８－羟基喹啉铝（Ａｌｑ３分散到聚乙烯基咔唑（ＰＶＫ）中的掺杂聚合物作为有源层制作的蓝绿发光二极管（ＬＥＤ），聚合物发光层用旋转涂敷的方法制备．ＩＴＯ／Ａｌｑ３：ＰＶＫ／Ａｌ器件在正向偏压为６Ｖ时可以看到蓝绿发光，峰值波长为５１０ｎｍ，最大亮度为１６８ｃｄ／ｍ２．     

Si1-XGeX/Si红外光电探测器

本文报导了用两种缓冲层生长技术研制的Ｓｉ１－ｘＧｅｘ／Ｓｉ异质结ｐｉｎ型红外探测器。其波长范围为０．７０～１．５５μｍ,峰值波长为０．９６～１．０６μｍ,暗电流密度低达０．０３μＡ／ｍｍ＾２（－２Ｖ）,在１．３μｍ处的响应度高达０．１５Ａ／Ｗ（－５Ｖ）;讨论了Ｇｅ组分、外延层厚度、偏置电压等对探测器参数的影响。     

高迁移率Si／Si_（0．7）Ge_（0．3）／Si调制掺杂异质结构的生长和输运性质

采用计算机控制的快速辐射加热、超低压ＣＶＤ（ＲＲＨ／ＶＬＰ－ＣＶＤ）方法生长了Ｓｉ／Ｓｉ０．７Ｇｅ０．３／Ｓｉｐ－型调制掺杂双异质结构．研究了该结构的输运性质，其空穴霍尔迁移率高达３００ｃｍ２／Ｖ·ｓ（３００Ｋ，薄层载流于浓度ｐｓ为２．６e１３ｃｍ－２）和８４００ｃｍ２／Ｖ·ｓ（７７Ｋ，ｐｓ为１．１e１３ｃｍ－２）．     

InGaN/AlGaN双异质结绿光发光二极管

报道了用 LP- MOVPE技术在蓝宝石 ( α- Al2 O3)衬底上生长出以双掺 Zn和 Si的 In Ga N为有源区的绿光 In Ga N/Al Ga N双异质结结构 ,并研制成功发射波长为 52 0— 540 nm的绿光LED.     

有机高亮度黄光发光二极管

用有机小分子制备的高亮度黄光电致发光器件,在１９Ｖ下器件亮度可达４００００ｃｄ／ｍ２,外量子效率达３．４％．     

多元多色HgCdTe红外探测器

简要介绍利用不同波段的微型滤光片和不同响应波段的多元ＨｇＣｄＴｅ红外探测器,叙述了通过精密镶嵌技术组合而成的四波段２１５～２２５μｍ、８４～８９μｍ、１０３～１１３μｍ和１１５～１２５μｍ８８元多元多色探测器的设计原理和特性,以及多元多色探测器的组合工艺,并给出了各个通道的响应光谱特性和探测器的工作性能。研制成功的８８元多色红外探测器每个通道的平均探测率和响应率分别为：Ｄ２．１５～２．２５＝１．２×１０１２ｃｍＨｚ１／２／Ｗ和Ｒ２．１５～２．２５＝５．０×１０６Ｖ／Ｗ,Ｄ８．４～８．９＝７．０×１０１０ｃｍＨｚ１／２／Ｗ和Ｒ８．４～８．９＝１．６×１０４Ｖ／Ｗ,Ｄ１０．３～１１．３＝４．０×１０１０ｃｍＨｚ１／２／Ｗ和Ｒ１０．３～１１．３＝４．３×１０３Ｖ／Ｗ,Ｄ１１．５～１２．５＝３．０×１０１０ｃｍＨｚ１／２／Ｗ和Ｒ１１．５～１２．５＝３．３×１０３Ｖ／Ｗ,文中对这些结果进行了分析和讨论。     

Multivariable backward-shift-invariant subspaces and observability operators

It is well known that subspaces of the Hardy space over the unit disk which are invariant under the backward shift occur as the image of an observability operator associated with a discrete-time linear system with stable state-dynamics, as well as the functional-model space for a Hilbert space contraction operator. We discuss two multivariable extensions of this structure, where the classical Hardy space is replaced by (1) the Fock space of formal power series in a collection of d noncommuting indeterminates with norm-square-summable vector coefficients, and (2) the reproducing kernel Hilbert space (often now called the Arveson space) over the unit ball in with reproducing kernel ). In the first case, the associated linear system is of noncommutative Fornasini–Marchesini type with evolution along a free semigroup with d generators, while in the second case the linear system is a standard (commutative) Fornasini–Marchesini-type system with evolution along the integer lattice . An abelianization map (or symmetrization of the Fock space) links the first case with the second. The second case has special features depending on whether the operator-tuple defining the state dynamics is commutative or not. The paper focuses on multidimensional state-output linear systems and the associated observability operators; followup papers Ball, Bollotnikov, and Fang (2007a, 2007b) use the results here to extend the analysis to represent observability-operator ranges as reproducing kernel Hilbert spaces with reproducing kernels constructed from the transfer function of a conservative multidimensional (noncommutative or commutative) input-state-output linear system.      

硅、锗和氩离子注入富硅二氧化硅的电致发光

将Si、Ge和Ar三种离子注入到磁控溅射制备的富硅二氧化硅和热生长的二氧化硅中,在N2气氛中,作550、650、750、850、950和1050℃退火后,进行电致发光研究.对比样品为退火条件相同的未经注入的上述两种二氧化硅.对于离子注入情况,只观察到Au/1050℃退火的离子注入的富硅二氧化硅/p-Si的电致发光.低于1050℃退火的离子注入富硅二氧化硅和上述各种温度下退火的热生长二氧化硅,无论离子注入与否,都未观察到电致发光.Au/未注入富硅二氧化硅/p-Si的电致发光光谱在1.8eV处出现主峰,在2.4eV处还有一肩峰.在Au/Si注入富硅二氧化硅/p-Si的电致发光谱中,上述两峰的     

Weight enumerator for second-order Reed-Muller codes

In this paper, we establish the following result. Theorem:A_i, the number of codewords of weightiin the second-order binary Reed-Muller code of length2^mis given byA_i = 0unlessi = 2^{m-1}or2^{m-1} pm 2^{m-l-j}, for somej, 0 leq j leq [m/2], A_0 = A_{2^m} = 1, and begin{equation} begin{split} A_{2^{m-1} pm 2^{m-1-j}} = 2^{j(j+1)} &{frac{(2^m - 1) (2^{m-1} - 1 )}{4-1} } \ .&{frac{(2^{m-2} - 1)(2^{m-3} -1)}{4^2 - 1} } cdots \ .&{frac{(2^{m-2j+2} -1)(2^{m-2j+1} -1)}{4^j -1} } , \ & 1 leq j leq [m/2] \ end{split} end{equation} begin{equation} A_{2^{m-1}} = 2 { 2^{m(m+1)/2} - sum_{j=0}^{[m/2]} A_{2^{m-1} - 2^{m-1-j}} }. end{equation}     

一种红光增强型白光LED特性研究

为了使白光LED光谱中红光成分增强,以更适应人眼视觉,通过对YAG:Ce荧光粉掺杂的改进,引入Gd3+、Pr3+使白光LED光谱在610 nm处出现明显发射峰,并且荧光主峰发生红移。通过对LED的色坐标计算表明,用这种新型荧光粉封装的白光LED色坐标可以达到标准白点(0.33,0.33),理论上有可能符合"能源之星"的要求,用YAG:Ce封装的LED却不可能。     

Estimation of Energy Aliasing Error for Nonbandlimited Signals

In this paper, we investigate the problem of approximating a given (not necessarily bandlimited) signal, x(t), by a (bandlimited) interpolation or sampling series of the form:

Color rendering and luminous efficacy of trichromatic and tetrachromatic LED-based white LEDs

White light-emitting diode (LED) spectra for general lighting should be designed for high luminous efficacy as well as good color rendering, which are generally in a trade-off relationship. White LEDs have uncountable metameres, they have different luminous efficacy and color rendering. Appropriate designed trichromatic and tetrachromatic LED-based white LEDs are presented that have acceptable color rendering as well as good luminous efficacy. Triachromatic white LEDs, with a wavelength combination of 460, 540, and 615 nm, offer high general color rendering index exceeding 89, and luminous efficacy 336 lm/W. The general color rendering index of tetrachromatic LED-based white LEDs combined from 460, 525, 590, and 640 nm is 95, the luminous efficacy is 306 lm/W. Further analysis shows the changing trends of the luminous efficacy, color rendering and the chromaticity coordinate of the optimized trichromatic and tetrachromatic white LEDs depending on the wavelength shift of the primary LEDs. For the optimized trichromatic white LEDs, both the luminous efficacy and color rendering change more with the wavelength shifts of the primary red LEDs than with the wavelength shifts of the blue and green LEDs. For the optimized tetrachromatic white LEDs, the changes of the luminous efficacy caused by the wavelength shifts of one red LED are smaller than the changes of trichromatic white LEDs. And the wavelength shifts of the red primary LED that have shorter wavelength affect the color rendering more than the other primary LEDs. The wavelength shifts of the blue primary LED change the chromaticity coordinate of the white LEDs more. The small changes of the chromaticity coordinate of the white LED do not mean small changes of the k and R_a.     

Lower bounds on lifetime of ultra wide band wireless sensor networks

The asymptotic lower bounds on the lifetime of time hopping impulse radio ultra wide band (TH-IR UWB) wireless sensor networks are derived using percolation theory arguments. It is shown that for static dense TH-IR UWB wireless sensor network, which sensor nodes are distributed in a square of unit area according to a Poisson point process of intensity n, the lower bound on the lifetime is \( \Upomega \left( {\left( {{{\sqrt n } \mathord{\left/ {\vphantom {{\sqrt n } {\log \sqrt n }}} \right. \kern-\nulldelimiterspace} {\log \sqrt n }}} \right)^{\alpha - 2} } \right) \), where α > 2 is the path loss exponent, thus dense TH-IR UWB wireless sensor network is fit to be employed in large-scale network. For static extended TH-IR UWB wireless sensor network which sensor nodes are distributed in a square \( \left[ {0,\sqrt n } \right] \times \left[ {0,\sqrt n } \right] \) according to a Poisson point process of unit intensity, the lower bound on the lifetime is \( \Upomega \left( {{{\left( {\log \sqrt n } \right)^{2 - \alpha } } \mathord{\left/ {\vphantom {{\left( {\log \sqrt n } \right)^{2 - \alpha } } n}} \right. \kern-\nulldelimiterspace} n}} \right) \), therefore large-scale extended network will lead to shorten network lifetime. The results also indicate that the lower bound on the lifetime in the ideal case is longer than that of a static network by a factor of \( n^{1/2} \left( {\log \sqrt n } \right)^{\alpha - 4} \). Hence mobility of sensor nodes can improve network lifetime.