论文标题
在合并的单取向WS2单层电影中，照明无形的晶界
Illuminating Invisible Grain Boundaries in Coalesced Single-Orientation WS2 Monolayer Films
论文作者
论文摘要
工程原子尺度缺陷对于实现用于电子设备的晶圆尺度单晶金属二甲藻单层单层至关重要。然而，将原子级缺陷与较大的形态相关的缺陷构成了重大挑战。使用电子显微镜和原子模拟，我们提供了对WS2晶体生长机制的见解，从而在合成条件与微观结构之间提供了直接联系。合并的单层WS2膜的暗场TEM成像照亮了原子分辨率STEM成像的缺陷阵列，将其识别为翻译晶界。成像揭示了薄膜具有几乎单个方向，并具有不完美的缝合域。通过原子分辨率成像和reaxff反应力场基分子动力学模拟，我们观察到了两种类型的翻译不匹配，并讨论了它们的原子结构和起源。我们的结果表明，不匹配是由相对快速的增长率引起的。通过对> 1300个方面的统计分析，我们证明了宏观结构特征是由纳米尺度的构建块构建的，描述了跨子 - Ångstrom到多微米长度尺度的系统。
Engineering atomic-scale defects is crucial for realizing wafer-scale, single-crystalline transition metal dichalcogenide monolayers for electronic devices. However, connecting atomic-scale defects to larger morphologies poses a significant challenge. Using electron microscopy and atomistic simulations, we provide insights into WS2 crystal growth mechanisms, providing a direct link between synthetic conditions and the microstructure. Dark-field TEM imaging of coalesced monolayer WS2 films illuminates defect arrays that atomic-resolution STEM imaging identifies as translational grain boundaries. Imaging reveals the films to have nearly a single orientation with imperfectly stitched domains. Through atomic-resolution imaging and ReaxFF reactive force field-based molecular dynamics simulations, we observe two types of translational mismatch and discuss their atomic structures and origin. Our results indicate that the mismatch results from relatively fast growth rates. Through statistical analysis of >1300 facets, we demonstrate that the macrostructural features are constructed from nanometer-scale building blocks, describing the system across sub-Ångstrom to multi-micrometer length scales.
