Electrical instability in a semiconductor gas discharge system

Electrical instability in a SI GaAs plates of the semiconductor gas discharge gap system (SGDGS) is studied experimentally in a wide range of the gas pressures, interelectrode distances and different diameters of the cathode areas. While being driven with a stationary voltage, it generates current and discharge light emission (DLE) instabilities with different amplitudes of the oscillation. It is shown that under the experimental conditions the interelectrode distance played only a passive role and was not responsible for the appearance of the DLE instability. At the same time for different diameters D of the GaAs plate areas the expanded range of current and DLE oscillations are observed. SGDGS with an N‐shaped CVC was analyzed using both the current and DLE data showing the electrical instability in the GaAs cathode. It was found that application of high feeding voltage to this cathode give rise to non‐uniform spatial distribution of the DLE, which disturbed the operation of the system. The experiment presents also a new metod to study and visualization of the electrical instabilities in high‐resistivity GaAs plates of large diameter. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

用1553nm激光脉冲触发GaAs光电导开关的研究

用15 5 3nm飞秒光纤激光器触发半绝缘GaAs光电导开关的实验表明,当光电导开关处于3 33～10 3kV/cm的直流偏置电场并被脉冲宽度2 0 0fs且单脉冲能量0 2nJ的激光脉冲照射时,开关表现为线性工作模式,开关输出峰值电压为0 8mV .分析表明,开关对波长为15 5 3nm触发激光脉冲表现出的弱光电导现象起因于半绝缘GaAs材料EL2深能级的作用.     

聚对苯撑苯并双(口恶)唑发光及其器件制备

采用光谱技术,研究了聚对苯撑苯并双(口恶)唑(PBO)溶液的光敏发光特性,并用相对法估算出溶液发光效率在50%范围.结合光谱技术、半导体电学和电化学等研究手段,具体研究了以PBO为发光层的单层电致发光器件,研究结果显示,电致发光与薄膜的光致发光有具有相同的发光中心,峰值位于510 nm左右.同时发现,由于存制备过程中不同处理条件使得不同厚度薄膜残留的掺杂物质浓度不同,从而引起薄膜的导电性的不同.使得器件的阈值场强随PBO厚度的减小而逐渐增加.     

具有NPB:DPVBi掺杂层的有机白光器件的研究

制作了结构为ITO／NPB（50nm）／NPB;DPVBi（10：1,30nm）／Alqs（20nm）／LiF（1nm）／Al的有机白光器件。由于掺杂层NPB：DPVBi的引入,电子及空穴容易被DPVBi及NPB俘获,提高激子的复合,进一步提高监光的发光能力。发光区从Alq3的发光峰逐渐变为DPVBi的发光和NPB发光增强,从而发光峰值发生变化。该器件的最大亮度和效率分别为22V时4721cd／m^2和5V时0．80cd／A。     

Oxygen-crosslinked polysilane: the new class of Si-related material for electroluminescent devices

The preparation and optical properties of the novel silicon-related material named oxygen-crosslinked polysilane were investigated. The oxygen-crosslinked polysilane was prepared by the thermal annealing of the precursor polysilane bearing alkoxyl groups. The photoluminescence consisting of a broad visible band at about 440 nm and a relatively sharp band at about 360 nm was observed at room temperature. The relative intensities of the visible emission were changed during the crosslinking. The visible emission was greatly affected by the steric hindrance of the alkoxyl groups of the precursor. The visible electroluminescene (EL) was also observed uniformly from the EL cell consisting of the oxygen-crosslinked polysilane film sandwiched between A1 electrode and indium-tin-oxide (ITO) electrode. The current densities of the EL cell increased with an increase in the oxygen-crosslinking. © 1997 John Wiley & Sons, Ltd.     

Tb配合物TbY(o-MOBA)6(phen)2·2H2O的电致发光器件

合成了一类新型稀土配合物TbY(o-MOBA)6(phen)2·2H2O,将其掺杂到导电聚合物聚乙稀咔唑(PVK)中获得了纯正、明亮的绿光发射.用这种掺杂体系分别制作了2类器件:1) ITO/PVK:TbY(o-MOBA)6(phen)2·2H2O/LiF/Al;2) ITO/PVK:TbY(o-MOBA)6(phen)2·2H2O/BCP/AlQ/LiF/Al.器件1的起亮电压为13 V,在21 V时最大亮度为18.2 cd/m2;结构优化的器件2,在23 V 时最大亮度可达124.5 cd/m2.将这种材料的发光性能与另一种稀土配合物Tb(o-MOBA)3phen·H2O相比较,并分别讨论了其光致发光(PL)和电致发光(EL)机理.     

Neuronal mechanism of epileptogenesis in EL mouse

The convulsions of the EL mouse (EL) were described by Imaizumi et al. in 1954 and were established as epilepsy by Suzuki in 1976. The EL mouse has been kept as an inbred strain and is considered one of the best animal models originated in Japan. The mode of inheritance is autosomal dominant, and environmental risk factors for seizure occurrence are hypothesised to contribute to the polygenic background. Paroxysmal activities in the EL brain arise from the parietal cortex (PCX) and are augmented in the hippocampus, demonstrated by electrophysiology and autoradiography using 2-deoxy glucose when clinical symptoms of seizures appeared. The neurons in the EL PCX, where GABA activity is lower than that of DDY PCX demonstrate increased excitability to proprioceptive sensory input. After repetitive seizure-provoking stimuli, seizures are more easily induced, eventually occurring spontaneously. This phenomenon of “abnormal plasticity” is also observed in the EEG, decreasing GABA activity, expression of the immediately early gene, and various biochemical and molecular processes. This phenomenon is similar to the learning or progressive process of certain neurological diseases.     

基于全集成自提取结终端隔离BCD新工艺的场致发光高压驱动芯片

本文提出可集成自提取结终端的0.35μm 150V-BCD （双极-互补金属氧化物半导体-双重扩散金属氧化物半导体）全套新型高压工艺．利用此工艺研制出100V场致发光用高低侧驱动芯片,并提出了基于双极器件BC （双极集电极）结短路自提取结终端新工艺与新结构,既可满足场致发光高压驱动芯片应用,又能取代传统采用氧化扩散工艺的P-ISO （P型隔离结构）传统隔离结构,显著简化了工艺和提高了芯片的高集成度,确保片内集成的低电阻率VDN-MOS/LDPMOS （N型垂直双扩散金属氧化物半导体场效应晶体管/P型横向扩散金属氧化物半导体场效应晶体管）高压驱动模块与低压逻辑控制模块在100V高压脉冲交替工作状况下无负电位、EMMI （微光显微镜）等寄生现象出现．     

Enhancement of light extraction efficiency of GaN-based light-emitting diode using ZnO sol-gel direct imprinting

ZnO nano-structures were formed on transparent conducting oxide layer of GaN LED device on non-patterned (non-PSS) and patterned sapphire substrates (PSS). Since ZnO nano-structures were formed by sol-gel direct imprinting process, plasma etching process, which may create the plasma induced damage, was not used. Due to the ZnO nano-structures, light extracted from active layer was coupled with ZnO nano-structures and thus total internal reflection at the ITO layer was suppressed. According to electroluminescence measurement, the emission intensities of GaN LED devices with ZnO nano-structures, on both non-PSS and PSS sapphire substrates were increased by 20.5% and 19.0%, respectively, compared to GaN LED devices without ZnO nano-structures, due to the suppression of total internal reflection. Moreover, it is confirmed that there is no decrease of light extraction on side direction due to light focusing to vertical axis by nanostructure. Electrical performance of GaN LED devices were not degraded by ZnO sol-gel direct imprinting process.