First-principles studies of MoF6 absorption on hydroxylated and non-hydroxylated metal oxide surfaces and implications for atomic layer deposition of MoS2
First-principles studies of MoF6 absorption on hydroxylated and non-hydroxylated metal oxide surfaces and implications for atomic layer deposition of MoS2
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DOI：
10.1016/j.apsusc.2020.148461
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发表时间：
2020-11
影响因子：
6.7
通讯作者：
M. Lawson;E. Graugnard;Lan Li
中科院分区：
文献类型：
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作者：
M. Lawson;E. Graugnard;Lan Li
对二维过渡金属二硫属化物的显著兴趣已经导致了使用可缩放的气相方法（例如化学气相沉积（CVD）和原子层沉积（ALD））对其合成的大量实验研究。ALD通常允许较低的沉积温度，并且化学前体的成核需要与表面官能团反应。用于研究ALD建模的常见第一性原理方法是计算所提出的反应途径的活化能。在这项工作中，我们计算的部分电荷密度，局域态密度（LDoS），Bader电荷分析，吸附能，和电荷密度差使用密度泛函理论（DFT）研究MoF6在三个氧化物表面上的成核，包括Al2O3，HfO2，和MgO。我们的研究结果表明，羟基（OH）有助于降低反应势垒在第一个半周期的MoF6和促进化学吸附的前体上的氧化物衬底。这一发现得到了氧化物表面形成的高离子MFX（M =金属，x = 1，2，3）键的支持。通过比较表面与羟基基团，我们强调了表面化学的重要性。
Significant interest in two-dimensional transition metal dichalcogenides has led to numerous experimental studies of their synthesis using scalable vapor phase methods, such as chemical vapor deposition (CVD) and atomic layer deposition (ALD). ALD typically allows lower deposition temperatures, and nucleation of chemical precursors requires reactions with surface functional groups. A common first-principles method used to study ALD modeling is the calculation of activation energy for a proposed reaction pathway. In this work we calculated the partial charge densities, local density of states (LDoS), Bader charge analysis, adsorption energies, and charge density difference using density functional theory (DFT) to investigate the nucleation of MoF6on three oxide surfaces, including Al2O3, HfO2, and MgO. Our findings indicate that hydroxyl groups (OH) help lower the reaction barrier during the first half-cycle of MoF6and promote the chemisorption of a precursor on the oxide substrates. This discovery is supported by the formation of highly ionic MFx(M = metal, x = 1, 2, 3) bonds at the oxide surfaces. By comparing surfaces with and without hydroxyl groups, we highlight the importance of surface chemistry.