The transition metal surface passivated edges of hexagonal boron nitride (h-BN) and the mechanism of h-BN's chemical vapor deposition (CVD) growth.
The transition metal surface passivated edges of hexagonal boron nitride (h-BN) and the mechanism of h-BN's chemical vapor deposition (CVD) growth.
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DOI：
10.1039/c5cp04833h
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发表时间：
2015-10
期刊：
影响因子：
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通讯作者：
Ruiqi Zhao;Feifei Li;Zhirong Liu;Zhongfan Liu;F. Ding
中科院分区：
文献类型：
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作者：
Ruiqi Zhao;Feifei Li;Zhirong Liu;Zhongfan Liu;F. Ding
在近热平衡条件下化学气相沉积（CVD）生长中，六方氮化硼（h-BN）畴的形貌和生长行为取决于边缘结构和稳定性。本研究通过密度泛函理论计算，探讨了用于h-BN CVD生长的三种典型过渡金属表面Cu（111）、Ni（111）和Rh（111）上h-BN的各种边缘。与真空中不同的是，我们的研究表明，在h-BN CVD生长的典型条件下，在所有探索的催化剂表面上，非六边形环（如五边形、七边形或它们的对）的形成在能量上不是优选的，锯齿形（ZZ）边缘比扶手椅（AC）边缘更稳定，这解释了三角形h-BN结构域的广泛实验观察。更重要的是，我们的结果表明，实验中观察到的三角形BN结构域可能不是以氮原子（ZZN）终止的原始ZZ边，而是由具有悬空原子的ZZ Klein边（ZZB + N或ZZN + b）包围的。通过应用Wulff构造理论，我们预测BN结构域的平衡形状可能是由富氮AC边包围的六边形。如果生长在富n、中性或富b环境中，则分别为两种不同类型的ZZ Klein边封闭的三角形或富硼AC边封闭的六边形。本研究提出了在CVD合成过程中如何控制h-BN结构域的边缘和平衡形状，并为进一步探索CVD制备的h-BN薄膜的生长行为和提高其质量提供了指导。
Edge structure and stability are crucial in determining both the morphology and the growth behaviours of hexagonal boron nitride (h-BN) domains in chemical vapour deposition (CVD) growth under near thermal equilibrium conditions. In this study, various edges of h-BN on three typical transition metal surfaces used for h-BN's CVD growth, Cu(111), Ni(111) and Rh(111), are explored with density functional theory calculations. Different from that in vacuum, our study shows that the formation of non-hexagonal rings, such as pentagon, heptagon or their pairs, is energetically not preferred and both zigzag (ZZ) edges are more stable than the armchair (AC) edge on all the explored catalyst surfaces under typical conditions of h-BN's CVD growth, which explains the broad experimental observation of triangular h-BN domains. More importantly, our results indicate that, instead of the pristine ZZ edge terminated with nitrogen atoms (ZZN), the triangular BN domains observed in experiments are likely to be enclosed with ZZ Klein edges having dangling atoms, ZZB + N or ZZN + B. By applying the theory of Wulff construction, we predicted that the equilibrium shape of a BN domain could be a hexagon enclosed with nitrogen-rich AC edges, triangles enclosed with two different types of ZZ Klein edges or a hexagon enclosed with boron-rich AC edges if the growth is in a N-rich, neutral or B-rich environment, respectively. This study presents how the edges and equilibrium shapes of h-BN domains can be controlled during the CVD synthesis and provides guidelines for further exploring the growth behaviours and improving the quality of CVD-prepared h-BN films.