DBM-g-PE与PVC的相互作用研究EI

采用固相接枝法制备了ＤＢＭ－ｇ－ＰＥ，用红外光谱分析证明了接枝物确实存在。ＰＶＣ／ＣＰＥ＝１００／５合金性能测定结果表明，添加５份接枝物的合金（Ａ），缺口冲击强度、拉伸强度分别为１８．２ｋＪ／ｍ２和５３．０ＭＰａ；而添加５份ＰＥ的合金（Ｂ），其相应性能为５．１ｋＪ／ｍ２和３３．８ＭＰａ。不加接枝物的合金（Ｃ），虽有高韧性，但拉伸强度却由５３．０ＭＰａ降至５０．２ＭＰａ。ＤＳＣ、ＳＥＭ的结果均表明，ＰＥ接枝ＤＢＭ后与ＰＶＣ的相互作用增强，与ＣＰＥ协同作用能增韧、增强ＰＶＣ，并探讨了其机理。     

聚酰亚胺LB膜MIS结构C—V特性

本文报道了Ａｌ／ＬＢ聚酰亚胺膜／Ｐ－Ｓｉ（１００）ＭＩＳ结构的Ｃ－Ｖ特性研究结果。６７层ＬＢ膜样品Ｃ－Ｖ特性近乎理想，具有负的固定电荷密度约１０＾１＾１ｃｍ＾－＾２量级，平带时滞后小于０．３Ｖ，对于ＭＩＳ隧道结，除了在－０．５－１．５Ｖ间具有反型层箝位产生的电容峰外，在－１．５－４Ｖ间还出现了另一电容峰值，假设在强电场下隧穿能力剧增，从而结构由隧穿限制区重新进入半导体限制区，可以解释这一峰值的出现     

高性能2.5Gb／s用的DFB—LD／EA单片集成器件

报导了采用全ＭＯＣＶＤ生长的１．５５μｍ的单片集成ＤＦＢ＝ＬＤ／ＥＡ组件的 在ＤＷＤＭ系统上的传输测试结果，出纤功率Ｐｆ≥２．５ｍＷ＠Ｉｆ＝７５ｍＡ，边模抑制比ＳＭＳＲ〉３５ｄＢ，调制器反向偏压为２．５Ｖ时的消光比为１４ｄＢ，该发射模块在２．５Ｇｂ／ｓＤＷＤＭ系统上进行了传输试验，传输２４０Ｋｍ后无误码，其通道代价≤１ｄＢ＠ＢＥＲ＝１０＾－１２。     

DMF中电沉积制备Yb-Co合金膜

研究了于室温下含有少量水的ＹｂＣｌ３－ＣｏＣｌ２－ＤＭＦ溶液中电沉积制备Ｙｂ－Ｃｏ合金膜。ＥＤＡＸ和ＸＲＤ分析表面：在０．１０ｍｏｌ／Ｌ ＹｂＣｌ３－０．１０ｍｏｌ／Ｌ ＣｏＣｌ２的ＤＭＦ电镀液中,以控制电位为－２．７５Ｖ（ＳＣＥ）进行恒电位电解,以控制电流密度为１００Ａ／ｍ＾２进行恒电流电解或以控制脉冲电流密度为１５０Ａ／ｍ＾２进行脉冲电解,可以得到不同形态和Ｙｂ含量的共沉积合金膜,且膜层光滑、     

PECVD法淀积氮化硼薄膜场发射特性研究

用 Ｂ２Ｈ６和 ＳｉＨ４作反应气体,通过射频等离子体增强化学气相淀积（ＲＦ－ＰＥＣＶＤ）方法,在 Ｓｉ（１００）面上沉积生长ＢＮ薄膜,用Ｓ－５２０扫描电子显微镜对所得薄膜进行观测,并用红外透射光谱测试分析了膜的成分。在室温、压力为 ８ × １０－４ Ｐａ条件下,对 ＢＮ薄膜的电流一电压特性进行测量,并得到了 Ｆｏｗｌｅｒ－Ｎｏｒｄｈｅｉｍ特性曲线,ＢＮ膜的场发射开启电场为９ Ｖ／μｍ,在电场３７．５ Ｖ／μｍ时,电流密度达到２４．８ ｍＡ／ｃｍ２。     

聚酰亚胺LB膜MIS结构C－V特性

本文报道了Ａｌ／ＬＢ聚酰亚胺膜／Ｐ－Ｓｉ（１００）ＭＩＳ结构的Ｃ一Ｖ特性研究结果．６７层ＬＢ膜样品Ｃ－Ｖ特性近乎理想，具有负的固定电荷密度约１０１１ｃｍ－２量级，平带时滞后小于０．３Ｖ对于ＭＩＳ隧道结，除了在－０．５—－１．５Ｖ间具有反型层箝位产生的电容峰外，在－１．５—－４Ｖ间还出现了另一电容峰值．假设在强电场下隧穿能力剧增，从而结构由隧穿限制区重新进入半导体限制区，可以解释这一峰值的出现，考虑到少子注入引入的扩散电容，正、反向扫描时电容峰值的差别可以得到解释     

SI—GaAs中的EL2和EL6缺陷团簇相关性研究

用光致电流瞬态谱（ＰＩＴＳ）方法研究了ＬＥＣＳＩ－ＧａＡｓ原生单晶经常规退火和等时快速退火（ＲＴＡ）深能级缺陷的变化。缺陷ＥＬ２（Ｅｃ－０．８２ｅＶ）ＥＬ１２（Ｅｃ－０．７９ｅＶ）表现出类似的ＲＴＡ特性，应属于ＥＬ２缺陷团簇；缺陷ＥＬ６（Ｅｃ－０．３８ｅＶ），ＥＬ８（Ｅｃ－０．２７ｅＶ）和ＥＬ９（Ｅｃ－０．２４ｅＶ０亦具有相似的ＲＴＡ特性，属ＥＬ６缺陷团簇。实验发现，在热退火中，ＥＬ２团簇缺陷密度     

SI－GaAs中EL2和EL6缺陷团簇相关性研究

用光致电流瞬态谱（ＰＩＴＳ）方法研究了ＬＥＣＳＩ－ＧａＡｓ原生单晶经常规退火和等时快速退火（ＲＴＡ）深能级缺陷的变化。缺陷ＥＬ２（Ｅｃ－０．８２ｅＶ）和ＥＬ１２（Ｅｃ－０．７９ｅＶ）表现出类似的ＲＴＡ特性，应属于ＥＬ２缺陷团簇；缺陷ＥＬ６（Ｅｃ－０．３８ｅＶ），ＥＬ８（Ｅｃ－０．２７ｅＶ）和ＥＬ９（Ｅｃ－０．２４ｅＶ）亦具有相似的ＲＴＡ特性，属ＥＬ６缺陷团簇。实验发现，在热退火中，ＥＬ２团簇缺陷密度减少，则ＥＬ６团簇缺陷密度增加；反之亦然，取决于退火温度的高低，表明ＥＬ２，ＥＬ６团簇在原子结构上相关。文中由此讨论了两个主要缺陷ＥＬ２和ＥＬ６的可能构型。     

立方A^4＋M^5＋2O7型化合物与新型负热膨胀材料

概述了立方Ａ＾４＋Ｍ＾５＋２Ｏ７型化合物的结构特点，讨论了ＡＶ２－ｘＰｘＯ７型（Ａ＝Ｚｒ或Ｈｆ；ｘ＝０．１～１．２）及其部分取代的Ａ＾４＋１－ｙＢ＾４＋ｙＶ２－ｘＰｘＯ７型（Ｂ＝Ｔｉ，Ｃｅ，Ｔｈ，Ｕ，Ｍｏ，Ｐｔ，Ｐｂ，Ｓｎ，Ｇｅ或Ｓｉ；ｙ＝０．１～０．４）和Ａ＾４＋１－ｙＣ＾１＋ｙＤ＾３＋ｙＶ２－ｘＰｘＯ７型（Ｃ为碱金属元素，Ｄ为稀土金属元素）材料的负热膨胀性能。     

阻燃半硬质LDPE/EVA泡沫塑料的研究

研究了添加型卤素阻燃剂、Ｓｂ２Ｏ２、Ａｌ（ＯＨ）３复合体系对ＬＤＰＥ／ＥＶＡ共混发泡体系的阻燃性能,并对制品结构与性能影响较大的因素进行了研究分析和讨论。实验结果表明,采用上述阻剂的复合体系对ＬＤＰＥ／ＥＶＡ发泡体系有良好的阻燃效果。制备出了氧指数为３５．５％,垂直燃烧性能达到了ＵＬ９４Ｖ－０级的ＬＤＰＥ／ＥＶＡ泡沫塑料。     

Defect engineering for high-power 780 nm AlGaAs laser diodes

Defect engineering is carried out to determine optimum growth conditions for highly reliable high-power 780 nm AlGaAs laser diodes (LDs) using deep level transient spectroscopy (DLTS). The DLTS results reveal that the defect density of the Al_0.48Ga_0.52As cladding layer depended heavily on growth temperature and AsH₃ flow but that of the Al_0.1Ga_0.9As active layer depended mostly on the growth rates of the active layer. As a result of layer optimization at growth condition by DLTS, a record high output power of 250 mW was obtained at an operating current as low as 129.6 mA under room temperature continuous wave (CW) operation.     

1.55 $mu$m InAs/InAlGaAs Quantum Dot DFB Lasers

For the fabrication of quantum dot (QD) distributed feedback (DFB) lasers, self-assembled InAs/InAlGaAs QDs were grown on the InP/InGaAs grating structures by a molecular beam epitaxy. Ridge-waveguide QD DFB lasers with a stripe width of 3 mum were fabricated. Single-mode lasing operation around the wavelength of 1.56 mum was successfully achieved under the pulsed and continuous-wave (CW) modes at room temperature. The lasing operation was also observed up to 70 degC under pulsed mode, which is the first observation on the single-mode lasing around 1.55 mum. The characteristic temperatures calculated from the temperature dependence of the threshold current density were 121.8 K from room temperature to 45 degC, which was reduced to 74.2 K from 45 degC to 70 degC.     

Low threshold current density, highly strained InGaAs laser grown by MOCVD

It is possible to delay the growth mode transition from a 2-D growth mode to 3-D growth mode (the so-called Stranski-Krastanov growth mode) by means of non-equilibrium growth process employing a low growth temperature and a high growth rate, and adopting a high V/III ratio simultaneously to maintain crystal quality. Record emission wavelengths in multiple InGaAs/GaAs quantum wells without a strain-compensated barrier are grown by metal organic chemical vapor deposition (MOCVD). An InGaAs vertical-cavity surface emitting laser (VCSEL) with emission spectrum up to 1.26 μm under CW operation has been realized. Optimizing the quality of InGaAs QWs leads to a low threshold current density. The qualities of the highly strained InGaAs QWs of this VCSEL structure, such as internal quantum efficiency, internal loss, and transparency current density, were investigated by standard broad area (BA) laser process. Combined with an extensive gain-cavity detuning and the high-quality InGaAs QWs, the InGaAs VCSEL, we believe, is a promising candidate for application to long wavelength, low-cost source fiber-optical communication systems.     

Fabrication of single-electron transistors using field-emission-induced electromigration

We report a novel technique for the fabrication of planar-type Ni-based single-electron transistors (SETs) using electromigration method induced by field emission current. The method is so-called "activation" and is demonstrated using arrow-shaped Ni nanogap electrodes with initial gap separations of 21-68 nm. Using the activation method, we are easily able to obtain the SETs by Fowler-Nordheim (F-N) field emission current passing through the nanogap electrodes. The F-N field emission current plays an important role in triggering the migration of Ni atoms. The nanogap is narrowed because of the transfer of Ni atoms from source to drain electrode. In the activation procedure, we defined the magnitude of a preset current Is and monitored the current I between the nanogap electrodes by applying voltage V. When the current I reached a preset current Is, we stopped the voltage V. As a result, the tunnel resistance of the nanogaps was decreased from the order of 100 T(omega) to 100 k(omega) with increasing the preset current Is from 1 nA to 150 microA. Especially, the devices formed by the activation with the preset current from 100 nA to 1.5 microA exhibited Coulomb blockade phenomena at room temperature. Coulomb blockade voltage of the devices was clearly modulated by the gate voltage quasi-periodically, resulting in the formation of multiple tunnel junctions of the SETs at room temperature. By increasing the preset current from 100 nA to 1.5 microA in the activation scheme, the charging energy of the SETs at room temperature was decreased, ranging from 1030 meV to 320 meV. Therefore, it is found that the charging energy and the number of islands of the SETs are controllable by the preset current during the activation. These results clearly imply that the activation procedure allows us to easily and simply fabricate planar-type Ni-based SETs operating at room temperature.     

RT-CW Operation of InGaN multi-quantum-well structure laser diodes

The continuous-wave operation of InGaN multi-quantum-well (MQW) structure laser diodes (LDs) was demonstrated at room temperature with a threshold current of 25 mA, a threshold voltage of 5.8 V, an output power of 30 mW and a high operating temperature of 100°C. The energy differences between the absorption and the emission energy of the InGaN MQW structure LDs were as large as 220 meV at RT. A deep localized state (the localization energy is >100 meV) was formed in the InGaN well layer due to the InGaN phase separation during the growth. Both the spontaneous emission and the stimulated emission of the LDs originated from these deep localized energy states. The far field pattern showed a higher order transverse mode of the entire 5-μm-thick epitaxial layer stack, with air and sapphire as the upper and lower cladding layers, respectively.     

Role of substrate current in the reliability life testing of gaas mmics

GaAs monolithic microwave integrated circuits (MMICs) typically show a dramatic increase in circuit current when operated above 200°C. This increase in current has been found to be in good agreement with a summation of the estimated substrate current flowing from the individual components of these circuits through the bulk GaAs to the back metalization. Although the substrate current for these MMICs was small at room temperature, it can be a substantial portion of the total circuit current at the high temperatures typical for accelerated life testing. A procedure was developed to compensate for the substrate current, thus allowing normal circuit operation during high temperature life testing.     

KY0.58Gd0.22Lu0.17Tm0.03(WO4)2 buried rib waveguide lasers

CW mirrorless laser operation at 1840 nm at room temperature was observed in buried rib waveguides of KY_0.58Gd_0.22Lu_0.17Tm_0.03(WO₄)₂ fabricated by structuring KY(WO₄) substrates by Ar-ion milling and subsequent liquid phase epitaxial growth of the active layer on these substrates. Laser efficiency and laser threshold seems to change with the width of the channels fabricated.     

Room temperature mass production of carbon nanotube field emission micro-cathode arrays using electroplating of a CNT/Ni composite followed by micro-machining

A room temperature fabrication method for the mass production of carbon nanotube (CNT) field emission micro-cathode arrays is reported. The technique combines electroplating of a CNT/Ni composite and micro-machining. This method combines the advantages of direct growth and screen printing conventionally used to fabricate such structures and avoids their disadvantages. Due to its integration and room temperature processing, the technique is proven to be advantageous in mass production and low cost. Results of field emission testing show that the CNT micro-cathodes have excellent field-emission properties, such as high current density (15.7 mA/cm²), field enhancement factor (2.4 × 10⁶/cm), and good stability (109 h for 10% degradation of current density from 400 μA/cm²).     

Field-induced electron emission from broad-area YBaCuO high-T c electrodes

A transparent anode facility has been used to compare the field-induced electron emission characteristics of planar YBaCuO high-T _c electrodes at room temperature and in the superconducting state. It was found that virgin electrodes under ambient conditions exhibit an initial current switch-on event at typical field levels of 30 MV m^–1, with the emission coming from a single point site: a large hysteresis effect was also observed when the field was cycled. In contrast, at low temperatures, no switch-on events were observed, and the hysteresis effect was significantly smaller. Also, if an emission current in the nanoamp range was recorded under constant-field conditions as the temperature was lowered through T _c, there was an abrupt (i.e. step-like) fall in both the emission current and its associated noise at the superconducting transition.     

A comparison between CW and pulsed mode operations of light-emitting devices based on alizarin violet

We have fabricated light-emitting devices based on alizarin violet. Transient responses of such devices have been studied by applying a sequence of two square-wave voltage pulses. Concentration of the active material in the emitting layer, and the amplitude of the voltage pulse have been varied to study the affects of space-charges in device operation. The devices have been operated under CW and pulsed modes. Current–voltage and luminance–current characteristics under two such modes have been compared. The rise in device temperature under CW mode has been estimated from the ratio of current densities in the two modes. Higher temperature under CW mode has resulted in lower luminance as compared to pulsed mode. © 2001 Kluwer Academic Publishers