Controlling the orientations of h-BN during growth on transition metals by chemical vapor deposition
Controlling the orientations of h-BN during growth on transition metals by chemical vapor deposition
复制标题
通过化学气相沉积在过渡金属上生长过程中控制 h-BN 的取向
DOI：
10.1039/c6nr09368j
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发表时间：
2017
期刊：
影响因子：
6.7
通讯作者：
Liu Zhongfan
中科院分区：
文献类型：
--
作者：
Zhao Ruiqi;Zhao Xiaolei;Liu Zhirong;Ding Feng;Liu Zhongfan
六方氮化硼（h-BN）在许多应用中至关重要，并且强烈期望其在大面积上以高质量合成。在过渡金属催化剂上进行化学气相沉积是合成h-BN的一种很有前途的方法，其中BN簇在初始生长中的排列决定了h-BN中缺陷的类型和数量。为了寻找更好的催化剂，我们系统地研究了h-BN团簇与各种金属表面之间的相互作用。结果表明，无论是面心立方（FCC）金属的（111）晶面还是六方密排（HCP）金属的（0001）晶面，几乎所有催化剂表面的团簇都存在两个取向相反的局部极小值。在初始生长过程中，h-BN团簇采用能量有利的位置，由于h-BN的边缘原子与下面的衬底之间的强相互作用，其注册表在进一步生长时被很好地保留。在FCC（111）上，h-BN畴总是以平行取向排列，而在HCP（0001）上，它们在同一平台上平行，在相邻平台上反平行。此外，在Ir和Rh的（111）面上，BhNt构型比BfNt构型更有利于能量的释放，其中下标h、t和f分别代表吸附位hcp、top和fcc。因此，Ir（111）和Rh（111）可以促进具有相同取向的h-BN畴的生长，这将通过减少形成晶界的可能性而大大改善h-BN的质量。
Hexagonal boron nitride (h-BN) is crucial for many applications, and its synthesis over a large area with high quality is strongly desired. A promising approach to synthesize h-BN is chemical vapor deposition on transition metal catalysts, in which the alignments of BN clusters in the initial growth determine both the types and the amounts of defects in h-BN. In the search for a better catalyst, we systematically studied the interactions between h-BN clusters and various metal surfaces. Our results show that the clusters on nearly all catalyst surfaces, no matter whether the (111) facets of face-centered cubic (FCC) metals or the (0001) facets of hexagonal close packed (HCP) metals, have two local minima with opposite orientations. During the initial growth, h-BN clusters adopt the energy-favored sites, whose registry is well preserved upon further growth owing to the strong interaction between the edge atoms of h-BN and the underlying substrates. On FCC(111), the h-BN domains are always aligned in parallel orientations, while on HCP(0001) they are parallel on the same terrace and anti-parallel on neighboring terraces. Beyond this, on the (111) surfaces of Ir and Rh, the BhNt configuration is much more energy favorable than BfNt, where, the subscripts h, t, and f represent the adsorption sites, hcp, top and fcc, respectively. Thus, Ir(111) and Rh(111) might promote the growth of h-BN domains with the same alignments, which will greatly improve the quality of h-BN by reducing the possibility of formation of grain boundaries.