共查询到20条相似文献,搜索用时 93 毫秒
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通过计算电子到达阴极面时的能量分布和求解电子隧穿表面势垒的薛定谔方程得到了透射式NEA GaAs光阴极发射电子能量分布的计算公式.利用该公式仿真研究了阴极表面势垒形状对电子能量分布的影响,发现I势垒变化对阴极的量子效率影响显著,其中尤以I势垒宽度影响更大,而Ⅱ势垒则影响阴极的能量展宽,其中真空能级的升高可使阴极电子能量分布更集中,但却牺牲了一定的阴极量子效率.拟合分析了实验测试的透射式阴极电子能量分布曲线,实验与理论曲线吻合得很好,并得到了阴极的表面势垒参数. 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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GaAs:Gs—O NEA光电阴极电子表面逸出几率的计算 总被引:5,自引:2,他引:3
介绍了计算CaAs:Cs-O NEA光电阴极电子表面逸出几率的方法,选用双偶极层表面模型,计算了两个极层形成的界面势垒各自对电子表面逸出几率的影响,提出了增大电子表面逸出几率的条件,并粗略推测了第一偶极层的厚度。 相似文献
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电子隧穿问题的数值算法 总被引:2,自引:0,他引:2
文中给出了计算电子隧穿问题的一种新的数值方法,该方法适用于任意形状的一维势垒。在该算法中,首先用Numerov算法注解薛定谔方程,然后再利用所得结果计算电子透射系数,为检测算法的精度,计算了电子对矩形双势垒及三角形势垒的透射系数,并与相应的精确解做了比较,结果表明该方法具有很高的精度。 相似文献
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利用FN电流估计薄栅MOS结构栅氧化层的势垒转变区的宽度 总被引:2,自引:2,他引:0
通过数值求解整个势垒的薛定谔方程 ,发现 FN电流公式中的 B因子强烈依赖势垒的转变区的宽度 ,而 C因子则弱依赖于势垒的转变区的宽度 .给出了一种利用 WKB近似所得的处理电子隧穿存在转变区势垒的过程 ,并得到一个 FN电流的分析表达式 .它可用来估计薄栅 MOS结构的栅氧化层的势垒转变区的宽度 .在转变区的宽度小于 1nm时 ,它与数值求解薛定谔方程的结果吻合得很好 ,表明该方法可以用来估计势垒转变区的宽度 .实验的结果表明 B因子随温度有较大的变化 ,这个结果验证了该方法的部分预测结果 相似文献
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Ling-Feng Mao 《Electron Devices, IEEE Transactions on》2008,55(3):782-788
A model is established to describe the temperature dependence of the electron tunneling current through HfO2 gate stacks based on analyzing the coupling between the longitudinal and transverse components of electron thermal energy caused by the difference of the effective electron mass between the HfO2 gate stacks and silicon. By analyzing the three-dimensional Schrodinger equation for a MOS structure with HfO2 gate stacks, a reduction in the barrier height is resulted from the large effective electron mass mismatch between the gate oxide and the gate (substrate). The calculated electron tunneling currents agree well with the experimental data over a wide temperature range. This coupling model can explain the temperature dependence of the electron tunneling current through HfO2 gate stacks very well. The numerical results also demonstrate that the temperature dependence of the electron tunneling current strongly depends on the effective electron mass of HfO2. This temperature sensitivity of the electron tunneling current can be proposed as a novel method to determine the effective electron mass of the gate oxide. 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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给出了一种利用 FN振荡电流的极值 ,测量电子在薄栅 MOS结构的栅氧化层中的平均有效质量方法 .利用波的干涉方法来处理电子隧穿势垒的过程 ,方便地获得了出现极值时外加电压和电子的有效质量之间的分析表达式 .用干涉方法计算所得到的隧穿电子在不同的 MOS结构的二氧化硅介质层中的有效质量表明 :它一般在自由电子质量的 0 .5 2— 0 .84倍的范围 .实验结果表明 :电子有效质量的值不随外加电压的变化而变化 ,并且对于相同的MOS结构 ,电子可能具有相同的有效质量 相似文献
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K. A. Svit D. Yu. Protasov L. L. Sveshnikova A. K. Shestakov S. A. Teys K. S. Zhuravlev 《Semiconductors》2014,48(9):1205-1210
Tunneling electron transport through CdS nanocrystal arrays fabricated by the Langmuir-Blodgett method are studied by scanning electron spectroscopy. The effect of the matrix-annealing atmosphere on tunneling transport through the nanocrystal arrays is studied. Electron capture at traps in the case of nanocrystals annealed in vacuum is detected by tunneling current-voltage characteristics analyzed using a model relating the data of tunneling spectroscopy, photoluminescence, and quantum-mechanical calculation. Analysis shows that the nanocrystal surface is passivated by an ammonia monolayer upon annealing in an ammonia atmosphere. It is found that the substrate and surrounding non-passivated nanocrystals have an effect on the electron polarization energy. 相似文献
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A method for measuring the characteristics of tunneling and impact ionization in thin-film electroluminescent emitters is suggested. This method makes it possible to find time dependences of the space-charge layer thickness near the anode and the length of the impact ionization region, to determine more exactly the time dependence of the field in the potential barrier at the cathode interface, the maximum depth of the surface states from which electron tunneling occurs, the minimum thickness of the barrier, and the electron tunneling probability, as well as the impact ionization rate for the deep centers related to structural defects of the phosphor layer. 相似文献
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Tunneling time asymmetry in semiconductor heterostructures 总被引:1,自引:0,他引:1
Analytical expressions are given for the difference between left-to-right and right-to-left tunneling times in asymmetric single- and multiple-barrier heterostructures. This tunneling time asymmetry is related to the phase difference of the reflection coefficients of the electron wavefunction for the two tunneling directions. Examples for single- and double-barrier heterostructures are given. The treatment in this paper can be used for designing devices with asymmetric frequency characteristics with respect to the electron tunneling direction 相似文献
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Quantum-mechanical modeling of electron tunneling current from the quantized inversion layer of ultra-thin-oxide (<40 Å) nMOSFET's is presented, together with experimental verification. An accurate determination of the physical oxide thickness is achieved by fitting experimentally measured capacitance-versus-voltage curves to quantum-mechanically simulated capacitance-versus-voltage results. The lifetimes of quasibound states and the direct tunneling current are calculated using a transverse-resonant method. These results are used to project an oxide scaling limit of 20 Å before the chip standby power becomes excessive due to tunneling currents, 相似文献