Zhuang Yuan, Que Yande, Xu Chaoqiang, Liu Bin, Xiao Xudong
Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong, People's Republic of China.
Post Doctocral Research Station, Shenzhen Capital Group Co. Ltd, Shen Zhen 518048, People's Republic of China.
Nanotechnology. 2021 Dec 15;33(9). doi: 10.1088/1361-6528/ac3d60.
Structural engineering opens a door to manipulating the structures and thus tuning the properties of two-dimensional materials. Here, we report a reversible structural transition in honeycomb CuSe monolayer on Cu(111) through scanning tunneling microscopy and Auger electron spectroscopy (AES). Direct selenization of Cu(111) gives rise to the formation of honeycomb CuSe monolayers with one-dimensional moiré structures (stripe-CuSe), due to the asymmetric lattice distortions in CuSe induced by the lattice mismatch. Additional deposition of Se combined with post annealing results in the formation of honeycomb CuSe with quasi-ordered arrays of triangular holes (hole-CuSe), namely, the structural transition from stripe-CuSe to hole-CuSe. Further, annealing the hole-CuSe at higher temperature leads to the reverse structural transition, namely from hole-CuSe to stripe-CuSe. AES measurement unravels the Se content change in the reversible structural transition. Therefore, both the Se coverage and annealing temperature play significant roles in the reversible structural transition in CuSe on Cu(111). Our work provides insights in understanding of the structural transitions in two-dimensional materials.
结构工程为操控二维材料的结构从而调整其性能打开了一扇门。在此，我们通过扫描隧道显微镜和俄歇电子能谱（AES）报告了在Cu(111)上的蜂窝状CuSe单层中的可逆结构转变。Cu(111)的直接硒化由于晶格失配在CuSe中引起的不对称晶格畸变，导致形成具有一维莫尔条纹结构（条纹-CuSe）的蜂窝状CuSe单层。额外的硒沉积与后退火相结合，导致形成具有准有序三角形孔洞阵列的蜂窝状CuSe（孔洞-CuSe），即从条纹-CuSe到孔洞-CuSe的结构转变。此外，在更高温度下对孔洞-CuSe进行退火会导致反向结构转变，即从孔洞-CuSe到条纹-CuSe。AES测量揭示了可逆结构转变过程中硒含量的变化。因此，硒覆盖率和退火温度在Cu(111)上的CuSe的可逆结构转变中都起着重要作用。我们的工作为理解二维材料中的结构转变提供了见解。
