共查询到19条相似文献,搜索用时 156 毫秒
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文章对电子透射几率问题进行了数值求解,这种方法能够处理形状复杂的一维势垒。首先利用龙格一库塔法和Numerov方法,联立求解薛定谔方程,然后利用得到的结果计算电子的透射几率,并考虑了计算误差的影响和减小方法。将该方法得到的数值解与精确值进行了比较,并用此方法考虑了不同双势垒结构中的共振隧穿问题。 相似文献
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共振隧穿是电子的隧穿概率在某一个能量值附近以尖锐的峰值形式出现的隧穿,是目前为止最有希望应用到实际电路和系统的量子器件之一,其特点是器件的响应速度非常快。本文用传递矩阵的方法分别计算了在外加偏压下,对称双势垒、三势垒应变量子阱结构的透射系数与入射电子能量和隧穿电流与偏置电压的关系,模拟了应变多量子阱结构的隧穿系数和I-V特性曲线。计算得到隧穿电流峰值位置与实验测试值符合得很好,对于设计共振隧穿二极管并为进一步实验提供理论指导具有重要的意义。 相似文献
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文中以探索多势垒结构的电子隧穿物理及其器件结构与性能为出发点,论述了多势垒结构隧穿现象的研究与进展。概述了一维半导体异质结构隧穿现象的解析解和数值计算。重点介绍了电子通过半导体双势垒结构产生隧穿现象的研究进展,即电子通过双势垒结构横纵波矢的耦合行为与共振准能级及共振准能级寿命的解析计算。 相似文献
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提出了一种精确求解隧穿电流的模型。通过自洽求解一维薛定谔方程和泊松方程,得到NMOS器件的半导体表面电势分布、反型层二维电子气的量子化能级以及对应的载流子浓度分布。为计算隧穿电流,采用了多步势垒逼近方法计算栅氧化物势垒层的隧穿几率,从而避免了WKB方法在突变边界处波函数不连续带来的缺陷。通过考虑(100)Si衬底的导带多能谷效应和栅极多晶硅耗尽效应,讨论了不同栅氧化层厚度下隧穿电流与栅压的依赖关系。模拟结果与实验数据吻合。 相似文献
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利用传递矩阵的方法研究了含有一个方势垒的单层石墨烯的隧穿特性,得到了透射概率与入射粒子费米能以及势垒宽度、势垒高度的变化关系,并且计算了势垒的结构参数及入射粒子费米能对低温电导的影响.这些结果可以为设计基于石墨烯材料的纳米器件提供理论参考. 相似文献
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基于精细积分法的耦合传输线瞬态分析 总被引:3,自引:0,他引:3
在耦合传输线的瞬态分析中提出了一种基于精细积分法的龙格-库塔迭代法。这是一种时域内的数值解法,该方法在对电报方程进行空间离散而获得对时间的一阶微分方程之后,没有采用精细计算法,而是采用了龙格-库塔迭代法。避免了大量的矩阵运算,提高了传输线瞬态响应分析的效率。 相似文献
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A simple transition between two sizes of rectangular waveguide is analyzed using the generalized telegraphist's equation. Solutions are obtained using a new moment method technique, a Runge-Kutta algorithm, and an iterative numerical integration technique. The results are compared to previously published experimental and numerical data. It is found that the numerical stability, accuracy, and consistency of the results are critically dependent on the choice of weighting and expansion functions. The best results for a simple rectangular-to-rectangular transition were obtained when Galerkin's method and triangle expansion functions were applied to several short sections which were then cascaded. Unlike the Runge-Kutta technique or the integration technique, the Galerkin's method procedure did not result in instabilities with the inclusion of evanescent modes. The programs can, in fact, be extended to any number of modes, the only apparent limitations being the obvious ones of computer time and memory 相似文献
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Calvez S. Rejeaunier X. Mollier P. Goedgebuer J.-P. Rhodes W.T. 《Lightwave Technology, Journal of》2001,19(6):893-898
We propose a new method for tuning an Er3+-doped continuous-wave fiber-ring laser. We present a novel numerical model and confirm the model with experimental results. The numerical model relies on the implementation of the analytical solution of signal propagation over small (elemental) segments of amplifier fiber rather than using the usual Runge-Kutta algorithm. The validity of the model is verified by the good agreement between computer results and experimental data. Experiments demonstrating a 11.2-nm wavelength tuning range have been conducted using an electrooptic intracavity filter composed of two cascaded unbalanced Mach-Zehnder interferometers (MZIs) integrated in lithium niobate. The numerical analysis shows that the tuning range obtained is limited by the combination of gain shape and filter characteristics. Increased tuning range can be obtained by decreasing losses or by using a more selective filter 相似文献
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Song Liu Shuangying Zhong Shaobin Liu 《Journal of Infrared, Millimeter and Terahertz Waves》2008,29(3):323-328
The electromagnetic propagation in dispersive media is modeled using finite difference time domain (FDTD) method based on the Runge-Kutta exponential time differencing (RKETD) method. The second-order RKETD-FDTD formulation is derived. The high accuracy and efficiency of the presented method is confirmed by computing the transmission and reflection coefficients for a nonmagnetized collision plasma slab in one dimension. The comparison of the numerical results of the RKETD and the exponential time differencing (ETD) algorithm with analytic values indicates that the RKETD is more accurate than the ETD algorithm. 相似文献
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耦合模方程一般是分析光纤光栅特性的出发点 ,在求解它的数值解法中 ,目前主要有龙格 -库塔法和矩阵分析法。介于这两种方法的差异 ,从一线性啁啾光纤光栅出发 ,比较它们得到的时延曲线。在相同的条件下 ,当波长增大时 ,前者所得的曲线中出现愈来愈明显的间断现象 ,且它与步长的选择无关 ,而后者所得时延曲线连续 ;但是增加取样点数 ,龙格 -库塔法所得时延轨迹的不连续情况可以被消除。因此在取样点数适当多时 ,龙格 -库塔法与矩阵分析法所得时延一致。 相似文献
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This paper compares three numerical methods for reliability calculation of Markov, closed, fault-tolerant systems which give rise to continuous-time, time-homogeneous, finite-state, acyclic Markov chains. The authors consider a modified version of Jensen's method (a probabilistic method, also known as uniformization or randomization), a new version of ACE (acyclic Markov chain evaluator) algorithm with several enhancements, and a third-order implicit Runge-Kutta method (an ordinary-differential-equation solution method). Modifications to Jensen's method include incorporating stable calculation of Poisson probabilities and steady-state detection of the underlying discrete-time Markov chain. The new version of Jensen's method is not only more efficient but yields more accurate results. Modifications to ACE algorithm are proposed which incorporate scaling and other refinements to make it more stable and accurate. However, the new version no longer yields solution symbolic with respect to time variable. Implicit Runge-Kutta method can exploit the acyclic structure of the Markov chain and therefore becomes more efficient. All three methods are implemented. Several reliability models are numerically solved using these methods and the results are compared on the basis of accuracy and computation cost 相似文献
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利用近共振激光驻波场操纵中性原子实现纳米级条纹沉积是一种新型的研制纳米结构长度标准传递方法,但仅通过一维和二维形式的仿真不能给出激光驻波场作用下中性原子沉积纳米光栅的全部信息。利用半经典模型,从铬原子在高斯激光驻波场中的运动方程出发,通过四阶Rungo-Kutta法模拟了铬原子在高斯激光驻波场中的三维运动轨迹以及三维沉积条纹结构,并分析了原子束发散、色差和球差等因素对三维运动轨迹及沉积条纹结构的影响。结果表明,利用三维仿真形式模拟高斯激光驻波场中铬原子的运动得到的结果与一维和二维形式下相比可以直观地表现出其较为详细的本质。 相似文献
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本文建立了MLS隧道器件的电流-电压特性的数值模拟程序,提出了一种新的计算方法:龙格-库塔数值积分与边界条件的预估-校正处理相结合的算法.利用建立的程序模拟计算了两种不同氧化层厚度的MIS隧道器件的电流-电压特性.对TiW/Si肖特基二极管,考虑了界面态的静态和动态影响,模拟特性和实验结果相比,令人满意的一致. 相似文献