论文标题
MOS2/HBN垂直异质结构的形成中范德华的微观机制
Microscopic mechanism of van der Waals heteroepitaxy in the formation of MoS2/hBN vertical heterostructures
论文作者
论文摘要
最近的作品表明，范德华（VDW）在晶体底物上的2D材料的外延生长，例如六角形硝酸盐（HBN），导致形成自对齐的晶粒，从而导致谷物之间无缺陷的缝线。但是，较弱的VDW相互作用如何导致谷物方向的强烈限制。在这项工作中，我们专注于研究MOS2晶粒在HBN上外延生长中自我调整的机制。通过基于密度功能理论和Lennard-Jones电位的计算，我们发现MOS2和HBN之间的相互作用能在很大程度上取决于MOS2的大小和方向。我们还发现，当MOS2的大小为大约时。 40 nm，旋转能屏障可以超过〜1 eV，即使在生长温度下，也应抑制旋转以限制MOS2的方向。
Recent works have revealed that van der Waals (vdW) epitaxial growth of 2D materials on crystalline substrates, such as hexagonal boron nitride (hBN), leads to formation of self-aligned grains, which results in defect-free stitching between the grains. However, how the weak vdW interaction causes strong limitation on orientation of grains is still not understood yet. In this work, we have focused on investigation of mechanism of self-alignment of MoS2 grains in vdW epitaxial growth on hBN. Through calculation based on density functional theory and the Lennard-Jones potential, we found that interaction energy between MoS2 and hBN strongly depends both on size and orientation of MoS2. We also found that, when size of MoS2 is ca. 40 nm, rotational energy barrier can exceed ~ 1 eV, which should suppress rotation to limit orientation of MoS2 even at growth temperature.
