Zhang Dong-Bo, Zhao Xing-Ju, Seifert Gotthard, Tse Kinfai, Zhu Junyi
College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875, China.
Beijing Computational Science Research Center, Beijing 100193, China.
Natl Sci Rev. 2019 May;6(3):532-539. doi: 10.1093/nsr/nwz014. Epub 2019 Jan 31.
The distribution of dopants significantly influences the properties of semiconductors, yet effective modulation and separation of -type and -type dopants in homogeneous materials remain challenging, especially for nanostructures. Employing a bond orbital model with supportive atomistic simulations, we show that axial twisting can substantially modulate the radial distribution of dopants in Si nanowires (NWs) such that dopants of smaller sizes than the host atom prefer atomic sites near the NW core, while dopants of larger sizes are prone to staying adjacent to the NW surface. We attribute such distinct behaviors to the twist-induced inhomogeneous shear strain in NW. With this, our investigation on codoping pairs further reveals that with proper choices of codoping pairs, e.g. B and Sb, -type and -type dopants can be well separated along the NW radial dimension. Our findings suggest that twisting may lead to realizations of - junction configuration and modulation doping in single-crystalline NWs.
掺杂剂的分布显著影响半导体的性能，然而，在均质材料中对p型和n型掺杂剂进行有效调制和分离仍然具有挑战性，尤其是对于纳米结构而言。通过采用结合支持性原子模拟的键轨道模型，我们表明轴向扭曲能够显著调制硅纳米线（NWs）中掺杂剂的径向分布，使得尺寸小于主体原子的掺杂剂倾向于占据NW核心附近的原子位点，而尺寸较大的掺杂剂则易于停留在NW表面附近。我们将这种不同的行为归因于NW中扭曲诱导的不均匀剪切应变。据此，我们对共掺杂对的研究进一步揭示，通过适当选择共掺杂对，例如硼（B）和锑（Sb），p型和n型掺杂剂可以在NW径向维度上得到很好的分离。我们的研究结果表明，扭曲可能会促成单晶NW中p-n结构型和调制掺杂的实现。
