Rurali Riccardo, Markussen Troels, Suñé Jordi, Brandbyge Mads, Jauho Antti-Pekka
Departament d'Enginyeria Electrònica, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
Nano Lett. 2008 Sep;8(9):2825-8. doi: 10.1021/nl801409m. Epub 2008 Aug 2.
At room temperature dopants in semiconducting nanowires are ionized. We show that the long-range electrostatic potential due to charged dopants has a dramatic impact on the transport properties in ultrathin wires and can virtually block minority carriers. Our quantitative estimates of this effect are obtained by computing the electronic transmission through wires with either charged or neutral P and B dopants. The dopant potential is obtained from density functional theory (DFT) calculations. Contrary to the neutral case, the transmission through charged dopants cannot be converged within a supercell-based DFT scheme, because the system size implied by the long-ranged electrostatic potential becomes computationally unmanagable. We overcome this problem by modifying the DFT potential with finite element calculations. We find that the minority scattering is increased by a factor of 1,000, while majority transmission is within 50% of the neutral dopant results.
在室温下，半导体纳米线中的掺杂剂会发生电离。我们表明，带电掺杂剂产生的长程静电势对超薄导线中的传输特性具有显著影响，并且实际上可以阻挡少数载流子。我们通过计算具有带电或中性P和B掺杂剂的导线的电子传输来获得这种效应的定量估计。掺杂剂势是通过密度泛函理论（DFT）计算得到的。与中性情况相反，基于超胞的DFT方案无法使通过带电掺杂剂的传输收敛，因为长程静电势所隐含的系统大小在计算上变得难以处理。我们通过有限元计算修改DFT势来克服这个问题。我们发现少数载流子散射增加了1000倍，而多数载流子传输在中性掺杂剂结果的50%以内。
