arXiv 2107.046962021-07-09cond-mat.mtrl-sciphysics.chem-ph

III-V量子点中表面和化学相关掺杂趋势的电子结构起源

Mapping the Electronic Structure Origins of Surface- and Chemistry-Dependent Doping Trends in III-V Quantum Dots

Michael G. Taylor, Heather J. Kulik

摘要：

通过引入掺杂原子来改变纳米结构材料的光电性能引起了人们的极大兴趣。然而，所采用的方法往往是试错法，妨碍了合理的设计。我们展示了大规模的电子结构计算的权力与密度泛函理论（DFT）建立一个地图集的优先掺杂剂的位置范围内的M（II）和M（III）的掺杂剂在代表性的III-V族InP魔术大小的集群（MSC）。我们量化了掺杂剂的热力学可掺杂性，我们将其确定为对MSC内的位点都是特异性的（即，内部与表面）以及掺杂剂原子的性质（即，较小的Ga（III）相对于较大的Y（III）或Sc（III））。这些观察结果激发了最有利和最不利的掺杂位点的地图的开发，这些地图与一些已知的实验预期一致，但也产生了意想不到的观察结果。对于等价掺杂（即，Y（III）/Sc（III）或Ga（III），我们观察到更强的灵敏度的预测能量的表面上的配体取向的类型比掺杂剂的类型，但发散行为观察内部掺杂是否是有利的。对于与M（II）的电荷平衡（即，Zn或Cd）掺杂剂，我们表明，在掺杂反应过程中除去的配体的类型是至关重要的。我们发现，有限的协同性与掺杂剂达到中等浓度发生，表明快速单掺杂剂的DFT的可扩展性的估计可以有效地指导合理的设计。我们的工作强调了配体化学和表面异质性在确定量子点中有利掺杂的路径中的重要性，这一观察结果对于通常用羧酸盐配体合成的其他III-V族和II-VI族量子点系统是通用的。

英文摘要：

Modifying the optoelectronic properties of nanostructured materials through introduction of dopant atoms has attracted intense interest. Nevertheless, the approaches employed are often trial and error, preventing rational design. We demonstrate the power of large-scale electronic structure calculations with density functional theory (DFT) to build an atlas of preferential dopant sites for a range of M(II) and M(III) dopants in the representative III-V InP magic sized cluster (MSC). We quantify the thermodynamic favorability of dopants, which we identify to be both specific to the sites within the MSC (i.e., interior vs surface) and to the nature of the dopant atom (i.e., smaller Ga(III) vs larger Y(III) or Sc(III)). These observations motivate development of maps of the most and least favorable doping sites, which are consistent with some known experimental expectations but also yield unexpected observations. For isovalent doping (i.e., Y(III)/Sc(III) or Ga(III), we observed stronger sensitivity of the predicted energetics to the type of ligand orientation on the surface than to the dopant type, but divergent behavior is observed for whether interior doping is favorable. For charge balancing with M(II) (i.e., Zn or Cd) dopants, we show that the type of ligand removed during the doping reaction is critical. We show that limited cooperativity with dopants up to moderate concentrations occurs, indicating rapid single-dopant estimations of favorability from DFT can efficiently guide rational design. Our work emphasizes the strong importance of ligand chemistry and surface heterogeneity in determining paths to favorable doping in quantum dots, an observation that will be general to other III-V and II-VI quantum dot systems generally synthesized with carboxylate ligands.

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英文摘要：

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