Te~ 离子注入溶液生长的Pb_(1-x)Sn_xTe制备P-N结

采用Te~ 离子注入使N型Pb_(1-x)Sn_xTe转变成P型层。Te~ 离子浓度大于1×10~(15)/厘米~2,并经适当的后退火处理在N型Pb_(1-x)Sn_xTe表面上产生大约1微米厚P型层。近年来,曾采用离子注入在Pb_(1-x)Sn_xTe晶体中制备P-N结,晶体的类型转变是由于用离子注入(如同化学掺杂)引进外来的原子或因注入产生的晶格缺陷造成的。在本文中,我们报导通过基质原子Te的注入控制化学计算的偏差使N型Pb_(1-x)Sn_xTe晶体类型转变。为了减少因注入而产生的晶格缺陷(贡献出N型电导)还需要适当的后退火。     

竖直液相外延炉生长Pb_(1-x)Sn_xTe/PbTe_(1-y)Se_y晶格匹配异质结激光器

本文根据Vagard定律,得到了Pb_(1-x)Sn_xTe/PbTe_(1-y)Se_y异质结晶格匹配条件,设计了生长参数,首次采用竖直液相外延炉生长了Pb_(1-x)Sn_xTe/PbTe_(1-y)Se_y品格匹配异质结,并制成了二极管激光器。     

一个估算重离子在SiO_2、Al_2O_3和Si_3N_4中的R_p和ΔR_p的经验公式

我们用中子活化分析和RBS技术测量了几种能量的~(73)As~+和~(132)Xe~+离子注入SiO_2和Al_2O_3膜的射程参数R_p和△R_p.把实验结果与投影射程统计计算的理论值作了对比.在总结国内外多种实验结果的基础上,找出了一个估算重离子(Z≥30,E=30-400KeV)在SiO_2、Al_2O_3和Si_3N_4中的R_p和△r_p的经验公式.该公式对R_p的估算值与多种实验值的差异一般小于10％、△R_p的差异一般小于15％.     

Pb_(1-x)Sn_xTe的液相电外延

用电流控制恒温液相外延生长Pb_(1-x)Sn_xTe对于2小时生长周期和电流密度5～17A/cm~2,生长温度在 450～600℃,得到 8～70μm生长层厚度。实验结果表明 Pb_(1-X)Sn_xTe的电外延能够在PbTe衬底上生长,且合金组份具有好的均匀性;外延层生长速度与电流密度成线性关系;Pb_(1-x)Sn_xTe中Sn的含量x_s随着电流密度的增加略有增加;实验中还发现生长速度随时间的延长而下降,这与H.C.Gatos提出Ga_(1-x)Al_xAs的电外延模型相似;还测定了电外延与温差外延固液线;对减少外延过程中产生回熔现象作了一些改进工作。     

Pb_(1-x)Sn_xTe闭管汽相输运过程的研究

用称量法可以迅速地测出Pb_(1-x)Sn_xTe闭管系统中水平汽相输运速度.研究了残余气体,例如过量的碲、铅及氧与氮的剩余气体对输运速度的影响.表明升华型材料的输运过程在温差小于 30℃时,输运速度没有出现饱和情况.我们建立了升华型物质的输运速度的关系式.充入已知量的氮气,根据输运速度的数据可以算出氮与Pb_(1-x)Sn_xTe的互扩散系数为0.013cm~2/sec.     

PMMA的离子束曝光特性

用B~+、F~+离子束曝光PMMA,实验得到灵敏度为(1-8)×10~(12)离子/厘米~2,饱和曝光深度t由能量损失的深度分布范围决定,且t≌R_p+2△R_p,阈值能量8_m=(30-330)焦耳/厘米~3,并估算了本实验条件下离子束曝光PMMA的分辨率d～(25-100)纳米.XPS分析结果表明,在剂量D>1×10~(13)离子/厘米~2时,PMMA表层中含氧量才显著减少,由此推想在离子束曝光常用剂量范围内,PMMA发生降解反应时并不伴随含氧侧基的脱落.     

资料简介索引

红外技术 1001 Pb_(1-x)Sn_xTe(0≤x≤0.25)光伏探测器的少数载流子寿命和电阻面积乘积 Photovoltaic detectors Pb_(1-x)Sn_xTe(0≤x≤0.25) minority carrier lifetimes resistance-area product, M. Grudzien, Infrared Phys., 1081, Vol. 21, No. 1, pp. 1-8. 计算了Pb_(1-x)Sn_xTe中辐射复合和俄歇复合时的少数载流子寿命。计算是在77、200和300K温度下进行的,组分范围为0≤x≤0.30。在附录中比较了在100K温度下的实验结果和理论计算。探讨了在77K时     

Pb_(1-x)Sn_xTe质子轰击和等时退火

采用质子轰击使x=0.20和x=0.24 P型Pb_(1-x)Sn_xTe转变为n型。质子能量在200和450千电子伏之间。对于初始浓度低于10~(17)/厘米~3范围的P型Pb_(0.80)Sn_(0.20)Te.用5×10~(17)质子/厘米~2的剂量就能转变为n型。对于浓度与其相当的P型Pb_(0.80)Sn_(0.20)Te要转变型号,剂量需高过5×10~(15)质子/厘米~2。迁移率的变化不大,一般不超过三倍。转了型的样品,迁移率一般增加。使用等时退火研究了由质子造成的效应的稳定性。发现,转为n型的x=0.20和x=0.24两类样品,在退火温度接近或低于140℃时要返回P型。     

用电子能谱法研究Pb_(1-x)Sn_xTe器件表面

一、引言化合物半导体红外探测器的表面性质往往限制了器件的性能。化合物半导体的表面钝化是一个重要问题,这至少部份是由于表面化学增加了复杂性,在多组份材料中这是可能出现的。Pb_(1-x)Sn_xTe属于经常出现明     

红外探测器:开管汽相迁移生长的Pb_(1-x)Sn_x Te外延膜

开管汽相迁移已经在Pb_(1-x)Sn_xTe(100)面衬底上面生长Pb_(1-x)Sn_xTe 外延膜。就表面光滑度和电气特性这两方面而论,原生长的膜适于制作探测器列阵。所利用的料源组分从过量1%金属到过量1%碲。所实现的生长速度为每小时高达3—4微米。原生长外延膜的载流子浓度在3×10~(16)厘米~(-3)——3×10~(17)厘米~(-3)范围内,与生长温度和料源组分有关。在未经表面处理的原生长的薄膜上面制作的带有半透明电极的肖脱基(Schottky)势垒探测器。20—40     

Theoretical studies of poly(para-phenylene vinylene) (PPV) and poly(para-phenylene) (PPP)

The electroluminescence from PPV and the blue light emission from PPP constitute exciting subjects of study. The band gap of these semiconducting polymers can be engineered in a wide range from red to ultraviolet by structural changes made on them. In the present work, we present a theoretical approach based on semiempirical and ab initio total energy and force calculations of PPV and PPP. We perform a conformational analysis in order to investigate the connection between their structural, optical and electronic properties. We use the large cell approach, in connection with the semiempirical quantum method Extended Hückel (BICON-CEDiT code) and the density functional theory (DFT) within the full-potential linearized augmented-plane-wave method (FPLAPW) as implemented in the computational code WIEN2k. Our results are compared to other calculations and to optical absorption measurements.     

(Sr_(0.5)Ba_(0.5))_(1.9)Ca_(0.1)NaNb_(5–x)TaxO_(15)陶瓷的介电性能

通过Ta掺杂改性钨青铜陶瓷(Sr0.5Ba0.5)1.9Ca0.1NaNb5–xTaxO15(x=0～0.30),分析了Ta掺杂量对其烧结性能、微观结构及介电性能的影响。陶瓷的烧结温度随x的增大略有提高。当x<0.10时,陶瓷的tC和弛豫性变化不大;当x≥0.10时,tm(1kHz)明显降低,从270℃(x=0)降低至231℃(x=0.30)。且tm随频率增加向高温移动,弛豫性明显增强。认为Ta掺杂引起其性能变化是由于Ta—O键与Nb—O键键能的差异,导致陶瓷氧八面体中心离子位移量以及A位离子有序程度的变化所致。     

Miniband spectra of (AlAs)M(GaAs)N(111) superlattices

Semiconductors - Electron states in the conduction band of (111)-oriented (AlAs)M(GaAs)N superlattices (SLs) with M≥N and N&;lt;10 are considered. The properties of such SLs are mainly...     

单层超晶格Ga_(0.47)In_(0.53)As/InP(110)及半导体合金Ga_(0.235)In_(0.765)P_(0.5)As_(0.5)的状态密度及介电常数(英文)

The DOS, JDOS and ε2(Ω) of monolayer superlattice Ga0.47ln0.53As/ InP(110) have been calculated by a tight-binding approach and compared with that of alloy Ga0.235ln0.765P0.5As0.5 which has the same stoi-chiometric composition as the monolayer superlattice. By using the techniques of the group theory we have obtained the expressions of momentum matrix elements between valence band states and conduction band states with four adjustable parameters. These parameters are determined by fitting the calculated values of ε2(Ω) with the experimental values for InP, GaAs and InAs. Our results show that the superlattice periodicity makes its DOS, JDOS and ε2(Ω) different from those of alloy in varying degree. Due to the folding of Brillouin zone, the JDOS of superlattice turns round in comparison with that of alloy. The momentum matrix elements have different effects for the superlattices and alloys.For the alloys, they can only change the amplitudes of peaks but not the positions of peaks; however, for the superlattices both amplitude and position can be changed.     

纳米复合(Nd,Pr)FeTiBC永磁合金的结构与磁性能

采用熔体快淬法制备了纳米复合(Nd1-xPrx)9.4Fe75.6Ti4B10.5C0.5(x为0,0.2,0.4,0.6,0.8和1.0)合金薄带,研究了Pr对合金薄带结构与磁性能的影响规律。结果表明:Pr降低了合金薄带的晶化温度,使合金薄带晶粒变得粗大,不利于合金矫顽力的提高。Pr对合金薄带磁性能的影响不大,不同Nd和Pr比例的合金薄带在最佳热处理条件下,剩磁Br在0.86 T与0.90 T之间,内禀矫顽力Hcj在1 000 kA/m左右,最大磁能积(BH)max介于130 kJ/m3与136 kJ/m3之间。     

Electromagnetic interference (EMI) of system-on-package (SOP)

Electromagnetic interference (EMI) issues are expected to be crucial for next-generation system-on-package (SOP) integrated high-performance digital LSIs and for radio frequency (RF) and analog circuits. Ordinarily in SOPs, high-performance digital LSIs are sources of EMI, while RF and analog circuits are affected by EMI (victims). This paper describes the following aspects of EMI in SOPs: 1) die/package-level EMI; 2) substrate-level EMI; 3) electromagnetic modeling and simulation; and 4) near electromagnetic field measurement. First, LSI designs are discussed with regard to radiated emission. The signal-return path loop and switching current in the power/ground line are inherent sources of EMI. The EMI of substrate, which work as coupling paths or unwanted antennas, is described. Maintaining the return current path is an important aspect of substrate design for suppressing EMI and for maintaining signal integrity (SI). In addition, isolating and suppressing the resonance of the DC power bus in a substrate is another important design aspect for EMI and for power integrity (PI). Various electromagnetic simulation methodologies are introduced as indispensable design tools for achieving high-performance SOPs without EMI problems. Measurement techniques for near electric and magnetic fields are explained, as they are necessary to confirm the appropriateness of designs and to investigate the causes of EMI problems. This paper is expected to be useful in the design and development of SOPs that take EMI into consideration.     

Sr_(0.3)Ba_(0.7)Bi_(3.7)La_(0.3)Ti_4O_(15)铁电陶瓷的烧结及介电性能

采用两步烧结工艺制备Sr0.3Ba0.7Bi3.7La0.3Ti4O15铁电陶瓷,研究了烧结工艺对陶瓷的晶相和介电性能的影响。结果表明:适当提高最高温度、保温温度和保温时间可改善陶瓷的介电性能。当最高温度为1180～1200℃,在1050～1080℃保温5～15h时,其εr为238～262,tanδ小于10–2,σ为1.0×10–11～10–12S·m–1。该烧结工艺可减少铋的挥发,降低氧空位浓度,因而减弱了陶瓷的高温低频耗散现象。随着保温时间的增加,高温电导得到有效抑制,在1050℃保温15h样品的σ降低了一个数量级,在280℃时为5.2×10–9S·m–1。     

sol-gel法制备Ba_(3.99)Sm_(9.34)Ti_(18)O_(54)微波介质陶瓷

以柠檬酸为络合剂,通过sol-gel法制备了Ba3.99Sm9.34Ti18O54陶瓷前驱体;经1100℃预烧2h压片成型后,再在1300℃保温3h,即得到了烧结致密的陶瓷样品。与传统固相法相比,其烧结温度降低了50℃,且陶瓷晶粒细小,晶粒分布均匀,具有更加优良的微波介电性能:εr=79.56,Q·f=9636GHz(4.71GHz),τf=–1.23×10–6/℃。     

MSTRIP (Parameters of Microstrip) (Computer Program Descriptions)

This program calculates the characteristic impedance, phase velocity, and effective dielectric constant of single or coupled microstrip lines. Parameters to be specified by the user are as follows: range of W/H/sub 1/, S/H/sub 1/, substrate dielectric constant, single or coupled lines with or without an upper ground plane.     

High-resolution transmission electron microscopy study of Ca(3)Co(4)O(9)

The crystal structure of Ca(3)Co(4)O(9) was investigated using high-resolution transmission electron microscopy (HRTEM) and the image-simulation method. The c(*) was 10.8A and the b parameters were 4.56A for the Ca(2)CoO(3) block and 2.82A for the CoO(2) sheet. The [110] zone axis HRTEM images confirmed that Ca(3)Co(4)O(9) has a modulated layered structure with modulation. For the first time, the atomic positions of the Ca and Co atoms in the Ca(2)CoO(3) block were identified, corresponding to three rows of dark spots in the [110] direction. The observed HRTEM images for Ca(2)CoO(3) agreed well with the calculated images based on the structural model obtained by the Rietveld refinement method.