聚合物发光器件中输运特性的模拟分析

对聚合物发光二极管I-V特性的测量发现,被测器件内存在着类似于某些无机器件中的负阻现象和"迟滞回线”状场致漂移的伏安特性.模拟分析表明,一种反向势垒的存在及其击穿,应是引起负阻现象的原因.缺陷态的存在及其电荷填充的变化,是导致I-V特性曲线随偏压扫描方向变化的主要原因.而低场下的接触性能决定着发光二级管载流子的输运性质:若为非欧姆接触,则I-V曲线可用F-N隧穿模型来描述;若为欧姆接触,则应用陷阱电荷限制电流(TCL)模型来描述.     

OLED器件电荷注入模型的MATLAB分析计算

介绍了电荷从OLED金属电极注入到一个随机跳跃体系（例如配对聚合物或分子掺杂聚合物）的模型。它包括电荷载流子从电极的费米能级到介质跳跃态分布尾态之间的注入,其结果可能是电荷载流子返回到电极,或者是受到镜像引力势的作用而形成扩散逃逸。后者类似于一维Onsager型激子解离。该模型将注入电流处理为电场、温度以及跳跃态分布能量宽度的函数。提出了OLED器件中相对电流密度的概念。介绍了用MATLAB软件分析计算该模型的方法和技巧。     

LiF层作为空穴阻挡层的绿色OLED的光电性能研究

采用真空热蒸镀方法,制备了四种Delta掺杂结构OLED器件,其结构为：ITO/m-MTDATA（50nm）/LiF（xnm）/NPB（10nm）/Alq（5nm）/C545T（0.05nm）/Alq（55nm）/LiF（1nm）/Al,都获得了性能稳定的绿色OLED器件。从实验结果分析可知：绿色OLED器件的电流-电压（I-V）特性曲线、亮度-电压（L-V）曲线、亮度-电流（L-I）曲线及效率等光电性能随着LiF厚度的变化而随之改变。从其中总结规律,对OLED器件制作工艺有一定的指导作用。     

Au/(Si/SiO2)/p-Si薄膜中电流及电致发光机制的分析

用射频磁控溅射法制备了具有Au／（Si／SiO2）／pSi结构的样品,利用I-V特性曲线和电致发光（EL）谱对载流子的输运及复合发光过程进行了研究,用位形坐标理论模型分析的结果表明,在SiO2薄膜中存在2个由于缺陷而形成的发光中心,Au膜中的电子和p型Si中的空穴在较高的电场下以Fowler-Nordheim（F-N）隧穿方式进入SiO2薄膜,并通过其中的缺陷中心复合而发光。     

基于PVK/PbS纳米晶有机无机复合薄膜电双稳器件性能研究

通过简单旋涂方法,制备了一种基于硫化铅（PbS）纳米晶与聚乙烯基咔唑（PVK）的有机/无机复合薄膜电双稳器件,并对所制备的器件进行性能测试及其电荷传输机制研究。首先采用热注入的方法制备了尺寸均一的立方形PbS纳米晶,然后将PbS纳米晶与PVK聚合物混合作为活性层材料,制备了有机/无机复合薄膜电双稳器件。该器件展示了良好的电双稳特性并且可以实现稳定的“读-写-读-擦”操作。器件的最大电流开关比能够达到10⁴。并进一步对器件在正向电压下的I-V曲线进行了理论拟合,发现在不同电流传导状态下,器件符合不同的电传导模型。进而分析了该电双稳器件中的电荷传输机制,认为在电场的作用下,发生在纳米晶与聚合物之间的电场诱导电荷转移是产生电双稳特性的主要原因。     

数值分析发光材料性质对OLED电流和亮度的影响

以具有指数分布的陷阱电荷限制电流为基础，用数值方法定量分析了单层有机电致发光器件（OLED）发光材料陷阱特性和发光层厚度对器件电流和亮度的影响。结果表明，电流密度和亮度随陷阱分布特征能级和有机层厚度的增大指数减小，并与总陷阱密度的1次方成反比，1为陷阱分布特征参数。     

聚合物发光器件中输运特性的模拟分析

对聚合物发光二极管 I- V特性的测量发现 ,被测器件内存在着类似于某些无机器件中的负阻现象和“迟滞回线”状场致漂移的伏安特性 .模拟分析表明 ,一种反向势垒的存在及其击穿 ,应是引起负阻现象的原因 .缺陷态的存在及其电荷填充的变化 ,是导致 I- V特性曲线随偏压扫描方向变化的主要原因 .而低场下的接触性能决定着发光二级管载流子的输运性质 :若为非欧姆接触 ,则 I- V曲线可用 F- N隧穿模型来描述 ;若为欧姆接触 ,则应用陷阱电荷限制电流 (TCL)模型来描述     

有机电致发光器件薄层掺杂对复合区位置的影响

以陷阱电荷限制传导模型为基础，研究了单层有机电致发光器件（OLED）的薄层掺杂对其复合区的影响。在掺杂区显增加的陷阱电荷，它能引起有机层内全部陷阱电荷的重新分布，会导致复合区位置向掺杂层方向移动。同时本对于实验数据进行了必要的理论计算及分析，得出了陷阱电荷限制模式下OLED薄层掺杂效应的定性数值结果。     

凌力尔特推出双通道DC/DC转换器 用于有源矩阵OLED和CCD偏置的升压型和负输出DC/DC转换器

凌力尔特公司（Linear Technology）推出双通道DC/DC转换器LT3582、LT3582-5和LT3582-12,这些器件提供了很多偏置应用所需的正和负输出,例如有源矩阵OLED（有机发光二极管）显示器以及CCD（电荷耦合器件）应如有源矩阵OLED（有机发光二极管）显示器以及CCD（电荷耦合器件）应用。     

基于有机p型掺杂电荷产生层制备叠层式白光OLED的研究

基于新型有机p型掺杂的电荷产生层,制备了叠层式白光有机发光二极管(OLED).有机p型掺杂层具有很高的导电率,可以在不影响器件电学特性的前提下,通过改变该层的厚度来优化白光OLED的器件性能,调节器件的光色.与传统白光OLED相比,文章研究的叠层式白光OLED制备工艺简单、电荷产生效率高,可应用于平板显示与固态照明.     

In-situ vacuum-sealed lateral FEAs with low turn-on voltage andhigh transconductance

We have fabricated a new lateral field emitter array, in-situ vacuum-sealed, which exhibits a low turn on voltage and a high transconductance value without any additional vacuum sealing process. The vacuum-sealed lateral FEA (VLFEA) is encapsulated during the fabrication process, so that field emission characteristics can be measured without any additional vacuum environments. Experimental current-voltage (I-V) characteristics show that the anode current is field emission current obeying the linearity of the Fowler-Nordheim (F-N) plot. The experimental turn-on voltage of about 9 V is in good agreement with the extracted one from the F-N plot. In order to verify the integrity of the vacuum sealed micro-cavity, we have measured the anode current of the VLFEA both in a high vacuum chamber and in an atmospheric environment and found that the structure is well sealed. The anode currents as a function of gate voltage of the Mo-sealed VLFEA are analyzed and transconductance is extracted. The experimental results show that the VLFEA has superior field emission characteristics, such as low turn-on voltage and high transconductance, and does not require any additional troublesome vacuum sealing     

一种新的应用到硅基有机发光二极管微显示像素电路仿真的OLED SPICE模型

本文介绍了一种新的OLED器件等效电路模型。由于单二极管模型能和多二极管模型一样较好的模拟OLED特性,因此新模型是基于单二极管模型建立的。并且为了保证拟合数据和测试数据有很好的一致性,在新模型中将常量电阻替换成指数电阻。通过与测试数据和其他两种OLED SPICE模型的模拟数据对比,新的模型更符合OLED的电流电压特性。新的模型能直接整合到SPICE电路仿真器中去,并且在OLED整个电压工作范围内拥有较好的仿真精度。     

Numerical Analysis on Current Transport Characteristics in Single Layer Organic Electroluminescent Devices

A new model to describe I-V characteristics of organic light-emitting devices (OLEDs) is developed based on experimental results. The dependence of I-V characteristics on energy barrier, trap density and carrier mobility is analyzed. The result shows that this model combines the Fowler-Nordheim tunnel theory and the trap charge limited current theory with exponential trap distribution (TCL), and it describes the current transport characteristics of OLEDs more comprehensively. The I-V characteristics follow Fowler-Nordheim theory when the energy barrier is high, the trap density is small and the carrier mobility is large.In other cases they follow the TCL theory.     

栅极宽度对IGBT通态压降的影响

利用silvaco软件对PT-IGBT的I-V特性进行了仿真,在同一电流密度下提取了不同栅极宽度IGBT的通态压降,得到了通态压降随栅极宽度变化的曲线,该仿真结果与理论分析一致。对于相同的元胞尺寸,栅极宽度存在最优值,只要合理地选取,可以有效地降低通态压降。     

Numerical analysis of slow current transients and power compression in GaAs FETs

Two-dimensional transient simulation of GaAs MESFETs is performed when the gate voltage and the drain voltage are both changed abruptly. Quasi-pulsed current-voltage (I-V) curves are derived from the transient characteristics. It is discussed how the slow current transients (lag phenomena) and the pulsed I-V curves are affected by the existence of substrate traps and surface states. It is shown that the so-called power compression could occur both due to substrate traps and due to surface states. Effects of impact ionization of carriers on these phenomena are also discussed. It is shown that the lag phenomena and the power compression are weakened when impact ionization of carriers becomes important, because generated holes may help the traps to change their ionized densities quickly.     

异质结载流子传输新模型

本文是针对异质结器件基础理论的不足,为建立一个改进理论系统所作努力的第二篇文章:提出了一个新的异质结I—V特性模型.这个工作给出了可以考虑“能场力”和“促扩力”的新能带图,系统的边界条件理论和能综合考虑“热发射”和“扩散”两种机制的pn异质结I—V特性理论.文中还提出了“准费米能级不连续性”、“载流子有效发射速度”等与传统观念不同的新概念.计算(p)GaAs-(N)AlGaAs异质结I—V特性与实验结果比较,结果是令人满意的.     

First-principles study on transport properties of zigzag graphene nanoribbon with different spin-configurations

The current-voltage(I-V) characteristics and the transmission spectra of zigzag graphene nanoribbon with different spin-configurations are investigated by using first-principles calculations.It is shown that the I-V curves and transmission spectra strongly depend on the spin-configurations of the two sides of the ribbon.For the spin-parallel configuration structure,the curve is linear under lower bias voltage;for the spin-antiparallel configuration structure,there is a strong spin-polarization-dependent transmission which implies that the ribbon can be used as a spin filter;while for other spin-configuration structures,the curve has the characteristics of a semiconductor. It is found that there is a large magneto-resistance(MR) when the bias voltage is small.The impurity in the central scattering region significantly influences the spin-dependent current and the spin filter efficiency,which may lead the large MR to disappear.     

Quantum-mechanical modeling of accumulation layers in MOS structure

An original method is used for the quantum-mechanical modeling of n-type silicon accumulation layers. Unlike previous methods, which were only valid near 4.2 K, the approach is valid up to room temperature and beyond. The self-consistent results obtained are compared with those of the standard classical model for the accumulation layer, and the differences between them are found to be relevant for the modeling of important device applications. The dependences of the accumulation voltage drop and effective F-N (Fowler-Nordheim) barrier height on oxide electric field and substrate dopine are reported. Experimental F-N current-voltage characteristics of production-quality MOS capacitors are used to validate the quantum results and to show that the standard classical model is not adequate even if the barrier height is considered as a fitting parameter. Approximate analytical expressions giving the semiconductor voltage drop and the effective F-N barrier height as a function of oxide field and substrate doping are derived for <100> and <111> n-type silicon at 77 and 300 K