Indium phosphide quantum dots (QDs) have emerged as a promising candidate to replace more toxic II–VI CdSe QDs, but production of high-quality III–V InP QDs with targeted properties requires a better understanding of their growth. We develop a first-principles-derived model that unifies InP QD formation from isolated precursor and early stage cluster reactions to 1.3 nm magic sized clusters and rationalize experimentally observed properties of full sized >3 nm QDs. Our first-principles study on realistic QD models reveals large surface-dependent reactivity for all elementary growth process steps, including In-ligand bond cleavage and P precursor addition. These thermodynamic trends correlate well to kinetic properties at all stages of growth, indicating the presence of labile and stable spots on cluster and QD surfaces. Correlation of electronic or geometric properties to energetics identifies surprising sources for these variations: short In···In separation on the surface produces the most reactive sites, at odds with conventional understanding of strain (i.e., separation) in bulk metallic surfaces increasing reactivity and models for ionic II–VI QD growth. These differences are rationalized by the covalent, directional nature of bonding in III–V QDs and explained by bond order metrics derived directly from the In–O bond density. The unique constraints of carboxylate and P precursor bonding to In atoms rationalize why all sizes of InP clusters and QDs are In-rich but become less so as QDs mature. These observations support the development of alternate growth recipes that take into account strong surface-dependence of kinetics as well as the shapes of both In and P precursors to control both kinetics and surface morphology in III–V QDs.

中文翻译：

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III–V量子点中表面依赖性生长的电子结构起源

磷化铟量子点（QD）已成为取代更具毒性的II–VI CdSe QD的有前途的候选者，但是具有目标特性的高质量III–V InP QD的生产需要对其生长有更好的了解。我们开发了第一性原理衍生的模型，该模型将InP QD的形成从分离的前体和早期簇反应统一到1.3 nm魔术大小的簇，并使全尺寸> 3 nm QD的实验观察到的特性合理化。我们对逼真的QD模型的第一性原理研究表明，所有基本生长过程步骤（包括配体内键裂解和P前体添加）都具有较大的表面依赖性反应性。这些热力学趋势与生长的所有阶段的动力学特性密切相关，表明簇和QD表面存在不稳定和稳定的斑点。电子或几何性质与高能的相关性为这些变化确定了令人惊讶的来源：短In···In分离在表面上产生的反应性最高，这与常规理解的对块状金属表面中应变（即分离）的认识有所不同，从而增加了反应性和离子II–VI QD生长的模型。这些差异可以通过III–V QD中键的共价，定向性质来合理化，并可以通过直接从In–O键密度中得出的键序度量加以解释。羧酸盐和P前驱体与In原子键合的独特约束合理化了为什么所有尺寸的InP团簇和QD都富含In，但是随着QD成熟而变得越来越小。