Silicon quantum dot superlattices: Modeling of energy bands, densities of states, and mobilities for silicon tandem solar cell applications
Silicon quantum dot superlattices: Modeling of energy bands, densities of states, and mobilities for silicon tandem solar cell applications
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DOI：
10.1063/1.2203394
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发表时间：
2006-06-01
影响因子：
3.2
通讯作者：
Green, MA
中科院分区：
文献类型：
--
作者：
Jiang, CW;Green, MA
量子点超晶格为新一代半导体器件提供了前景。最近提出的一个可能的应用是完全基于硅的串联太阳能电池，使用量子点中的限制来控制电池带隙。在本文中，我们使用有效质量的方法来计算的导带结构的三维硅量子点超晶格的点嵌入在二氧化硅，氮化硅，或碳化硅的矩阵。量子点超晶格被建模为相应矩阵中的等尺寸立方体点的规则间隔阵列。消除硅各向异性有效质量的影响，以减少各向同性解决方案的退化和状态之间的能量分离。电子态密度和迁移率来自能带结构数据。得到了点尺寸、点间距和基体材料对膜厚影响的理论结果。这些结果阐明了所提出的全硅叠层太阳能电池所需的硅量子点超晶格的设计特征。
Quantum dot superlattices offer prospects for new generations of semiconductor devices. One possible recently suggested application is in tandem solar cells based entirely on silicon, using confinement in the quantum dot to control the cell band gap. In this paper, we use the effective mass approach to calculate the conduction band structure of a three-dimensional silicon quantum dot superlattice with the dots embedded in a matrix of silicon dioxide, silicon nitride, or silicon carbide. The quantum dot superlattice is modeled as a regularly spaced array of equally sized cubic dots in the respective matrix. Incorporating the effect of silicon anisotropic effective mass is shown to reduce both the degeneracies of the isotropic solutions and the energy separation between states. Electron densities of state and mobilities are derived from the band structure data. Theoretical results for the effect of dot size, interdot distance, and matrix material have been obtained. These results clarify the required design features of silicon quantum dot superlattices for the proposed all-silicon tandem solar cells.