Department of Chemistry, National University of Singapore , Singapore 117543.
Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore , Singapore 117546.
Nano Lett. 2017 Feb 8;17(2):1116-1120. doi: 10.1021/acs.nanolett.6b04715. Epub 2017 Jan 20.
Two-dimensional (2D) transition metal dichalcogenides (TMDCs) possess interesting one-dimensional (1D) properties at its edges and inversion domain boundaries, where properties markedly different from the 2D basal plane, such as 1D metallicity and charge density waves, can be observed. Although 2D TMDCs crystals are widely grown by chemical vapor deposition (CVD), the fabrication of 1D TMDCs ribbons is challenging due to the difficulty to confine growth in only one dimension. Here we report the controlled growth of MoSe nanoribbons with an aspect ratio >100 by using prepatterned Se reconstructions on Au(100). Using scanning tunneling microscope and spectroscopy (STM/STS), the atomic and electronic structure of MoSe nanoribbons are studied. The ultranarrow ribbons show metallic behavior, while wider ribbons show a crossover from metallic to semiconducting behavior going from the edge to the center of the ribbon. The observed conductance modulations of the ultranarrow ribbons are attributed to 1D Moiré pattern. Remarkably, it shows a different periodicity compared with the 2D Moiré pattern in wider ribbons indicating that the 1D system is softened due to the high ratio of edge to basal plane bonds. Further, we demonstrated that the nanoribbons are stable against ambient conditions, which suggests that 1D TMDCs can be exploited for further applications.
二维（2D）过渡金属二卤化物（TMDC）在其边缘和反演畴界处具有有趣的一维（1D）性质，在这些性质中可以观察到与二维基底平面明显不同的性质，例如 1D 金属性和电荷密度波。尽管 2D TMDC 晶体已广泛通过化学气相沉积（CVD）生长，但由于难以仅在一维上限制生长，因此制备 1D TMDC 纳米带具有挑战性。在这里，我们报告了通过在 Au（100）上使用预图案化的 Se 重构来控制生长具有 >100 的纵横比的 MoSe 纳米带。使用扫描隧道显微镜和光谱学（STM/STS）研究了 MoSe 纳米带的原子和电子结构。超窄纳米带表现出金属行为，而较宽的纳米带则表现出从边缘到中心的金属到半导体行为的交叉。观察到超窄纳米带的电导调制归因于 1D Moiré 图案。值得注意的是，与较宽纳米带中的二维 Moiré 图案相比，它显示出不同的周期性，这表明由于边缘与基底平面键的高比例，1D 系统变软。此外，我们证明纳米带在环境条件下是稳定的，这表明 1D TMDC 可以用于进一步的应用。
