Atomic layer deposition (ALD) and molecular layer deposition (MLD) are key techniques used to fabricate high-quality thin films. Organic α,ω-bifunctional precursors often exhibit different growth behaviors depending on the functional groups as well as the chain length of the molecular backbone, so that some organic precursors produce thin films of organic-inorganic hybrid materials, while others may deposit purely inorganic thin films without incorporation of the hydrocarbon moiety. In this study, we investigated the surface reaction mechanisms of α,ω-bifunctional molecules (X(CH)X, n = 2, 3, 4, 5, 6, and X = OH, SH, NH) with diethylzinc toward MLD and ALD using density functional theory (DFT) calculations. It was found that the length of the aliphatic alkyl chain and the terminal functional groups of bifunctional organic precursors significantly influences their reactivity, resulting in the possibility toward removal or incorporation of the organic moiety in the product. Bifunctional reactants with longer alkyl backbones (n > 4) showed higher reactivity for removal of the hydrocarbon chain, facilitated by a ω-2 hydrogen transfer reaction. Furthermore, a reactivity trend of SH > OH > NH for removal of the hydrocarbon chains was observed. Our study provides in-depth theoretical insights into the adsorption reaction mechanisms occurring when bifunctional molecules are employed as organic reactants in ALD and MLD processes.

中文翻译：

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α,ω-双功能分子原子层沉积与分子层沉积的反应机制

原子层沉积（ALD）和分子层沉积（MLD）是用于制造高质量薄膜的关键技术。有机α,ω-双功能前驱体通常根据官能团以及分子主链的链长表现出不同的生长行为，因此一些有机前驱体产生有机-无机杂化材料的薄膜，而其他有机前驱体则可能沉积纯无机薄膜。不掺入烃部分的薄膜。在这项研究中，我们研究了α,ω-双功能分子（X(CH)X, n = 2, 3, 4, 5, 6, and X = OH, SH, NH）与二乙基锌对MLD和ALD 使用密度泛函理论 (DFT) 计算。研究发现，双官能有机前体的脂肪族烷基链和末端官能团的长度显着影响其反应性，从而导致产物中有机部分的去除或结合的可能性。具有较长烷基主链 (n > 4) 的双功能反应物在去除烃链方面表现出更高的反应性，这得益于 ω-2 氢转移反应。此外，观察到去除烃链的反应活性趋势为SH > OH > NH。我们的研究为 ALD 和 MLD 过程中双功能分子用作有机反应物时发生的吸附反应机制提供了深入的理论见解。