Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, P. R. China.
Nanoscale. 2017 Jun 8;9(22):7501-7507. doi: 10.1039/c7nr01609c.
Lateral heterostructures of 2D materials have several interesting properties and potential applications, and they are usually fabricated by chemical vapor deposition. However, it still remains a great challenge to fabricate 2D lateral heterostructures with well-controlled patterns and sharp interfaces. Herein, we found that the 2D α-MoC crystal, a recently emerging 2D superconductor, experiences a phase transition from the α phase to β phase on electron beam irradiation in a transmission electron microscope because of the migration of carbon atoms among the molybdenum octahedrons. Combined with first-principles calculations, the carbon atom migration paths and the corresponding energy barriers were discussed. Utilizing this unique phase transition property of 2D α-MoC crystal, we demonstrated the precise in situ construction of the lateral heterostructure of 2D superconducting α/β MoC with a well-controlled pattern and sharp interface using advanced aberration-corrected scanning transmission electron microscopy.
二维材料的横向异质结构具有若干有趣的性质和潜在应用，通常通过化学气相沉积来制备。然而，用具有良好可控图案和锐利界面的方法来制备二维横向异质结构仍然是一个巨大的挑战。在此，我们发现，二维α-MoC 晶体是一种新出现的二维超导体，在透射电子显微镜中的电子束辐照下，由于钼八面体之间的碳原子迁移，它经历了从α 相到β 相的相变。结合第一性原理计算，讨论了碳原子迁移路径和相应的能量势垒。利用二维α-MoC 晶体的这种独特相变特性，我们使用先进的相衬校正扫描透射电子显微镜，展示了具有良好可控图案和锐利界面的二维超导α/β MoC 横向异质结构的精确原位构建。
