准垂直肖特基二极管电极间距对耐压的影响

研究了不同电极间距对准垂直肖特基势垒二极管（SBD）正反向I-V特性，尤其是击穿电压和漏电的影响。通过制备不同电极间距的准垂直GaN SBD，测量不同电极间距器件的击穿电压和反向漏电变化。测量发现当电极间距小于器件台面刻蚀深度时，器件的击穿电压随着电极间距的增大而增大；当电极间距大于台面刻蚀深度时，器件的击穿电压随着电极间距的增大而几乎不发生变化。利用Silvaco软件进行了一系列的仿真研究，发现SBD的峰值电场强度不仅取决于电极间距，同时还受限于台面高度。研究表明在准垂直SBD研制中，为得到高击穿电压，电极间距应匹配器件台面的高度。     

表面阳极氧化铝结构对ZnO薄膜探测器的响应增强

通过在ZnO外延薄膜上淀积一层Al薄膜,并利用Al膜叉指型光刻胶图案为掩模,可以选择性地将叉指间无光刻胶区域下的Al膜阳极氧化,在ZnO表面形成氧化铝微纳结构,而在光刻胶掩模下未被阳极氧化的Al膜便成为ZnO紫外光电导探测器的叉指电极.用此法制备的非周期性氧化铝结构具有相近的孔大小和间距,形成可以在平面内全方位大角度衍射的光栅矢量.入射光可以被ZnO有阳极氧化铝结构的探测器比无此结构的器件在同等条件下的光响应度提高到了1.8倍.     

场板结构浅平面结高压器件

本文采用浅平面结制作场板结构高压器件，根据二维模拟器件击穿电压分析结果选择器件参数：深，场氧化层厚度，场板宽度和内部电极间距。结果，半绝缘钝化结构击穿电压的计算值与实验值相关较大，而绝缘层钝化结构的两者较接近。     

MIM开关器件的伏安特性研究

研究了MIM器件的电导机制，详细介绍了新提出的MIM器件的p-n^--n能带模型，同时利用这一能带模型解释并验证了上电极材料的选择，下电极材料掺N以及用溅射Ta2O5膜代替阳极氧化T2O5膜作绝缘层对MIM器件伏安特性曲线对称性的影响。利用p-n^--n能带模型首次提出用在氢气气氛下热处理的阳极氧化Ta2O5膜作MIM器件的绝缘层可以提高器件的I－V特性曲线的对称性这一新实验方法，另外，本文还较为详细地讨论了阳极氧化过程对MIM器件特性的影响，并首次讨论了对阳极氧化Ta2O5膜进行热处理时，退火方式和反应室气压变化对MIM器件I－V特性的影响。     

聚合物脊形波导定向耦合电光开关的电极优化

给出了一种新型聚合物脊形波导定向耦合电光开关的结构模型和设计方法.应用保角变换法和镜像法分析了对称共面双电极的电场分布.为了获得最小的模式损耗和开关电压,优化了电极厚度、电极宽度和电极间距.为了使器件实现正常的开关功能,讨论了所能允许的开关电压的波动范围.模拟计算结果如下:脊形波导的芯宽度4.0μm,芯厚度1.5μm,脊高0.5 μm,耦合间距3.0μm,优化后的电极厚度0.15 μm,电极宽度3.0μm,电极间距3.5μm,耦合长度3 082μm,开关电压5.43 V;当开关电压在5.28到5.59 V范围内波动时,器件的插入损耗小于0.60 dB,串扰小于-30 dB.与BPM仿真结果的对比表明,该优化方法具有较高的精度.     

行波电极型BOA光开关的研制

设计了行波电极型GaAs异质结材料BOA光开关;采用谱域法分析和设计了平面微带线结构(PMS),并应用转移矩阵理论和有效折射率法计算和分析了电极结构与器件半波电压和串音度的关系。结果表明,采用PMS结构器件的3dB带宽可达到20GHz;电极位置的对称性对器件串音度起决定性的影响,采用本文提出的电极对准工艺,能够得到小于—40dB的串音度。     

平面型纳米真空三极管的计算机模拟

平面纳米真空三极管只需要平面工艺,与现有的微电子工艺兼容,与基于经典Spindt阴极的真空微电子三极管相比,具有工艺相对简单等特点,同样具备纳米真空电子器件抗辐射、温度稳定性好等优点。本文采用粒子模拟方法对平面型纳米真空三极管的场发射特性进行了计算机模拟研究,模拟中考虑了空间电荷的影响。典型器件的模拟结果表明,平面型纳米真空三极管具有信号响应速度快,工作电压较低等优点。研究了该三极管结构中的尖端曲率半径、尖端相对高度、栅极电压和阳极电压对场发射特性的影响,有助于设计和优化该类器件结构。这种平面型纳米真空三极管可望成为真空集成电路的基础器件,并在卫星等航空航天领域等需要抗辐射领域获得应用。     

掺杂聚苯胺有机高分子发光器件

采用聚苯胺作阳极,ＭＥＨ－ＰＰＶ作发光材料,我们合成了有机高分子发光二极管器件．通过对聚苯胺的掺杂,发现器件的发光强度比未掺杂器件提高３０％,起始工作电压降低２５％．寿命测量还显示以聚苯胺或掺杂聚苯胺作电极的二极管器件,在给定电压下的工作寿命要比直接用导电玻璃作电极的二极管器件提高７～１０倍以上．     

一种背面深槽填充P型多晶硅RC-IGBT

提出了一种新型RC-IGBT,在背面阳极处设置了填充重掺杂P型多晶硅的深槽和FOC浮空电极。器件正向导通时,利用重掺杂P型多晶硅与N型衬底的接触电势差,将槽间的N型衬底部分耗尽,增强了阳极PN结的短路电阻,在较短背面阳极尺寸的条件下实现了RC-IGBT在开启过程中不出现电压折回现象。在器件反向开启过程中,空穴电流经过FOC浮空电极流入P型多晶硅,降低了多晶硅与N型衬底之间的势垒,提高了反向二极管的开启速度,降低了开启过程中二极管的过充电压。仿真结果表明,提出的新型RC-IGBT完全消除了电压折回现象,反向电流的均匀性得到了提高。相比于传统RC-IGBT,该新型RC-IGBT的元胞背面尺寸减小了88.89%,关断损耗降低了26.37%,反并联二极管的反向恢复电荷降低了13.12%。     

用化学镀方法在不同衬底上制备纳米尺度金属插塞电极的研究

纳米尺度金属插塞电极在现代纳米电子学中有很重要的应用价值。本文研究了用化学镀方法制备纳米尺度金属插塞电极,具有简单、低成本和自选择性的优点。化学镀甚至可以分别在硅衬底、钨衬底和氮化钛衬底上制备出直径小于50纳米的镍插塞电极。用能量色散X射线微量分析仪（EDXM）测定出用化学镀在硅衬底上制备出的纳米尺度插塞电极的主要成分是镍。最后,采用化学镀方法,制备了直径为9微米的插塞电极的垂直结构相变存储器器件。通过研究器件的电流-电压特性表明,化学镀方法可以满足器件应用要求。因此,用简单、低成本的化学镀方法来制备纳米尺度金属插塞电极,对器件的应用有重要意义。     

碳纳米管阴极平板显示器的工艺研究

碳纳米管场致发射显示器是一种新型的真空器件，也是一种具有巨大应用潜力的平板型显示设备。本文详细地介绍了碳纳米管场致发射原理，给出了碳纳米管阴极平板显示器的基本结构和工作原理，对于显示器件的真空封装，碳纳米管阴极装配，控制栅极制作等工艺问题进行了阐述和研究。采用这些技术，已经研制出了碳纳米管阴极场致发射显示器的样品。     

Investigation on the Low Luminous Efficiency in a Polymer Light‐Emitting Diode with a High Work‐function Cathode by Soft Contact Lamination**

This article reports the main origin of the low luminescent efficiency in hole‐dominant polymer light‐emitting diodes by controlling the hole injection and by chemically modifying the cathode by molecular monolayers. Since molecular modification of the top electrode is impossible when one deposits the electrode using a vacuum deposition method, this study was performed using a soft contact lamination technique to form electrical contacts on top of the emissive layer. The top electrode was chemically modified with an alkane thiol self‐assembled monolayer (SAM) to act as an interfacial spacer layer between the emitting layer and the cathode. Herein, it is reported that, contrary to common belief, a high device quantum efficiency can be achieved from the dominantly hole‐transporting device with a high work‐function cathode (like Au) by facilitating more hole injection from the anode in the device with low population of exciton quenching channels near the cathode.     

CMOS-compatible organic light-emitting diodes

We report a new method for the integration of light-emitting devices on a silicon substrate. As an active layer, we use unsubstituted PPV or PPV-based organic macromolecules with a p⁺-silicon anode and a cathode made from aluminum or titanium. The polymer is deposited by spin-coating the precursor, followed by a thermal conversion step to form the macromolecules. All process steps, including the possibility of dry etching of the active layer and the upper electrode, are typical for MOS technology. Spectrum analysis, current-voltage, and intensity measurements have been carried out for device characterization. These organic light-emitting diodes allow the monolithic integration of microelectronic circuits and light-emitting devices on one silicon chip applying only typical MOS process steps     

A Versatile Buffer Layer for Polymer Solar Cells: Rendering Surface Potential by Regulating Dipole

Spin‐coated film of poly(vinylidenefluoride‐hexafluoropropylene) (P(VDF‐HFP)) acts as a cathode/anode buffer layer in polymer solar cells (PSCs) with conventional/inverted device structures. Such devices show optimized performances comparable with the controlled device, making P(VDF‐HFP) a good substitute for LiF/MoO₃ as a cathode/anode buffer layer. Ultraviolet photoelectron spectroscopy (UPS) and Kelvin force microscope (KFM) measurements show that increased surface potential of active layers improves cathode contact. In piezoresponse force microscopy (PFM) measurement, P(VDF‐HFP) responds to applied bias in phase curve, showing tunable dipole. This tunable dipole renders surface potential under applied bias. As a result, open‐circuit voltage of devices alters instantly with poling voltage. Moreover, positive poling of P(VDF‐HFP) together with simultaneous oxidation of Ag gradually improves performance of inverted structure device. Integer charge transfer (ICT) model elucidates improved electrode contacts by dipole tuning, varying surface potential and vacuum level shift. Understanding the function of dipole makes P(VDF‐HFP) a promising and versatile buffer layer for PSCs.     

ELECTRON GUN FOR LARGE ORBIT GYROTRON (LOG) WITH DECREASED INFLUENCE OF CATHODE PLASMA ON ELECTRON BEAM PROPERTIES

High power Large Orbit Gyrotron (LOG) [1] is now under development at FIR FU. First version of this device was recently manufactured and then assembled with power supply ETIGO-IV [2]. Results of preliminary tests of electron-optic system are presented. The conditions when stable flat form of current pulse realized are discussed. Analytical estimations of cathode-anode distance to achieve small influence of cathode plasma during high voltage (HV) pulse are performed. Two new electron gun versions with decreased influence of the cathode plasma on its impedance and pulse form are suggested and optimized. New optimal magnetic field distributions are found. First gun has quiasi-flat cathode configuration near the anode diaphragm and provides operating current about 60 A. Second one uses blade cathode with operating current about 30 A. Beam quality for both guns is suitable for LOG operation.     

Performance of microdischarge devices and arrays with screenelectrodes

Cylindrical microdischarge devices, 50-150 μm in diameter and fabricated in Ni-polyimide-Cu or Ni foil structures, have been operated with Ni or Cu screens serving as the anode and/or cathode. As compared with annular anode (open bore) designs, the installation of at least one screen electrode has the effect of lowering the device operating voltage by as much as 30% while raising the electron temperature of the plasma. As a result, microdischarge devices 50 μm in diameter operate at voltages below 95 V at a Ne gas pressure of 700 torr, exhibit hollow cathode operation at gas pressures beyond 300 torr (or at least a factor of three higher than those observed previously), and the power output of a device with an anode screen operating at 300 torr is double that of its no-screen counterpart. Screen electrodes also stabilize the ignition characteristics of arrays and extend device lifetimes     

单层OLED器件模型的MATLAB分析计算

近年来有机发光二极管(OLED)的工业应用特别是在平板显示器中的应用已被广泛研究.OLED发光是分别由阴极和阳极注入的电子和空穴在发光层中复合的结果.单层结构是OLED器件的基础.为了提高OLED器件的性能,需要详细理解电荷载流子的注入过程.借助MATLAB求解了无量纲单层OLED器件模型,介绍了有关分析计算方法和技巧.综合利用MATLAB提供的符号求解常微分方程、绘图等命令,可使工作量大为减少.该方法具有编程简单,使用方便、实用性强等特点.     

Carbon Nanotube-Based Triode Field Emission Lamps Using Metal Meshes With Spacers

We fabricated a carbon nanotube (CNT)-based triode field emission flat lamp with a gated emitter structure, which is composed of a metal grid with a spacer as a gate, a cathode electrode layer, and a CNT layer. The metal mesh was designed with trenches and numerous holes to make a gap between gate and cathode electrodes and to provide electrons with a highly efficient passage. We observed that this metal mesh decreased the vibration and leakage current owing to high electric field generated from anode. As a result, the uniformity and stability of this field emission lamp was improved     

On relationship between the field at an autoemitter top, anode voltage and cathode geometry

Currently a lot of electron emission experiments both in carbon nanotubes with top curvature radius <1 nm, and in emitters as short as 10³ nm with top curvature radius of some tens nanometer are carried out. Experimental results can be explained by a tunnel emission through potential barrier in vacuum near the solid-state cathode border making use of Fowler-Nordheim law. However, in case of cathodes with radius of top curvature less than 100 nm this law is not valid.To proof this statement, the potential of an autoemission diode consisting of a tip cathode located on a flat metal base and flat anode, its dependence on the shape, height of the tip as well as voltage drop on it were calculated in this paper. It has been shown that with cathode tip height and its radius of curvature decreasing (?100 nm) the transparency of the potential barrier depends non-linearly on the anode voltage in the Fowler-Nordheim coordinates when the cathode tip height decreases from 1000 down to 150 nm. To obtain a measurable autoemission current, work function must not exceed the uniform field’s potential drop between cathode top and its base. Deduced is the analytic formula for the electric field potential that extends approximation features for real cathodes shapes and enables more accurate electric field modeling at the surface.     

基于MIC多晶硅薄膜阳极的微腔有机发光器件

通过对溶液法金属诱导晶化多晶硅薄膜制备工艺的优化,制备出性能良好的P型掺杂多晶硅薄膜。厚度为50nm的MICP+-Poly-Si薄膜的方块电阻可降低至400Ω左右,其光学特性表现为在红光区域具有比较高的反射率和很小的吸收率,因此用它替代ITO用作红光OLED的阳极材料。由于此薄膜对可见光比较高的反射率和阴极铝对可见光的高反射性,使之形成了一定Q值的微腔效应。结果显示该器件的最大流明效率为5.88cd/A,比用ITO作阳极制备的OLED提高了57%。进一步优化器件结构,调整发光层在腔中的最佳位置,可以大大增强发光强度,从而可以实现发光强度高、单色性好的红色微腔有机电致发光显示器件。