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基于经验赝势法得到的能带结构数据,采用分段多项式拟合获得ZnS能带结构的解析表达式,建立解析能带模型.使用建立的模型计算得到各能谷的态密度和总的散射速率,并与文献的计算结果进行了对比,验证该解析能带模型既具有非抛物型多能谷能带模型运算速度快、使用方便的优势,又具有与采用全导带模型相近的计算精度.进一步利用该模型进行蒙特卡罗模拟,得到第一导带和第二导带中电子数随电场强度的变化、不同电场中能量分布函数以及包含与不包含碰撞离化情况下电子能量随时间变化的曲线.讨论在外加电场下,电子在导带内各个能谷间和导带间的输运特性,揭示了谷间和带间散射在电子能量分布中的作用,特别是碰撞离化在电子能量分布和电流倍增中起到的重要作用.这些结论对研究提高薄膜电致发光器件的性能有一定的指导意义.
Based on the energy band structure data obtained from empirical pseudopotential method, the analytic expression of ZnS band structure was obtained by piecewise polynomial fitting, and the analytic energy band model was established.The state density and total scattering of each energy valley were calculated using the established model The experimental results show that the analytical band model not only has the advantage of fast computing speed and convenient operation, but also has the similar calculation accuracy as the all-band model The model is further used to simulate Monte Carlo to obtain the change of the number of electrons in the first conduction band and the second conduction band with the electric field strength, the energy distribution function in different electric fields, and the electron energy with and without collision ionization The curves of the electron transport in the energy bands and the conduction bands in the conduction band under the applied electric field are discussed.The effects of the valley and interband scattering on the electron energy distribution are discussed, Electron energy distribution and current multiplication plays an important role in the conclusion of these conclusions for the study to improve the performance of thin-film electroluminescent devices have some guidance.