Modeling of surface roughness scattering in nanowires based on atomistic wave function: Application to hole mobility in rectangular germanium nanowires
Modeling of surface roughness scattering in nanowires based on atomistic wave function: Application to hole mobility in rectangular germanium nanowires
复制标题
基于原子波函数的纳米线表面粗糙度散射建模：在矩形锗纳米线空穴迁移率中的应用
DOI：
10.1103/physrevb.93.155303
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发表时间：
2016
影响因子：
3.7
通讯作者：
and Tsunenobu Kimoto
中科院分区：
文献类型：
--
作者：
Hajime Tanaka;Jun Suda;and Tsunenobu Kimoto
作者提出了一种基于反紧束缚方案对电子态的原子描述的纳米线（NW）表面粗糙度散射（SRS）计算模型，然后将该模型应用于矩形截面的锗（Ge）纳米线中的空穴传输。在该SRS模型中，首先计算由于宽度或高度减小而导致的电子能带结构的变化，然后使用表面附近的等效电势来表示。根据该等效电势计算对应于表面粗糙度的扰动。使用上述 SRS 模型，考虑声子散射和 SRS 来计算 Ge 纳米线中的空穴迁移率。分析了SRS对Ge纳米线空穴迁移率的影响，重点关注纳米线的价带结构和空穴态。主要结果如下。在低空穴密度下，SRS的影响很大程度上取决于纳米线的几何形状，而具有高声子限制空穴迁移率的Ge纳米线，例如沿[001]方向具有较大高度的矩形横截面[110]取向的纳米线和方形横截面[111]取向的纳米线，往往受SRS的影响较小。然而，在高空穴密度下，空穴迁移率的几何依赖性变得较弱。这些可以从空穴态的性质和价带结构来理解。
The authors present a calculation model of surface roughness scattering (SRS) in nanowires (NWs) based on atomistic description of electronic states by antight-binding scheme, and then this model is applied to hole transport in rectangular cross-sectional germanium (Ge) NWs. In this SRS model, the change of electronic band structures due to width or height reduction is first computed, and then it is expressed using an equivalent potential near the surface. The perturbation corresponding to a surface roughness is calculated from this equivalent potential. Using the aforementioned SRS model, hole mobility in Ge NWs was computed taking into account phonon scattering and SRS. The impacts of SRS on hole mobility in Ge NWs were analyzed, focusing on the valence band structure and hole states of NWs. The main results are as follows. At low hole density, the impacts of SRS are strongly dependent on NW geometry, and Ge NWs with high phonon-limited hole mobility, such as rectangular cross-sectional [110]-oriented NWs with large height along the [001] direction and square cross-sectional [111]-oriented NWs, tend to be less affected by SRS. At high hole density, however, the geometry dependence of hole mobility becomes weaker. These are understood from the nature of hole states and the valence band structure.