Huang Chaoqin, Xie Lei, Zhang Huan, Wang Hongbing, Hu Jinping, Liang Zhaofeng, Jiang Zheng, Song Fei
Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201000, China.
University of Chinese Academy of Sciences, Beijing 101000, China.
Nanomaterials (Basel). 2022 Jul 22;12(15):2518. doi: 10.3390/nano12152518.
Vanadium diselenide (VSe), a member of the transition metal dichalcogenides (TMDs), is proposed with intriguing properties. However, a comprehensive investigation of VSe (especially regarding on the growth mechanism) is still lacking. Herein, with the molecular beam epitaxy (MBE) measures frequently utilized in surface science, we have successfully synthesized the single-layer VSe on Au(111) and revealed its structural transformation using a combination of scanning tunneling microscopy (STM) and density functional theory (DFT). Initially, formation of the honeycomb structure is observed with the moiré periodicity, which is assigned to VSe. Followed by stepwise annealing, defective structures with streaked patterns start to emerge due to the depletion of Se, which can be reversed to the pristine VSe by resupplying Se. With more V than Se deposited, a new compound that has no bulk analogue is discovered on Au(111), which could be transformed back to VSe after providing excessive Se. As the realization of manipulating V selenide phases is subtly determined by the relative ratio of V to Se and post-annealing treatments, this report provides useful insights toward fundamental understanding of the growth mechanism of TMDs and might promote the wide application of VSe in related fields such as catalysis and nanoelectronics.
二硒化钒（VSe）作为过渡金属二硫属化物（TMDs）的一员，具有引人关注的特性。然而，目前仍缺乏对VSe的全面研究（尤其是其生长机制方面）。在此，借助表面科学中常用的分子束外延（MBE）方法，我们成功地在Au(111)上合成了单层VSe，并结合扫描隧道显微镜（STM）和密度泛函理论（DFT）揭示了其结构转变。最初，观察到具有莫尔周期性的蜂窝状结构，其被认定为VSe。随后进行逐步退火，由于硒的耗尽，开始出现带有条纹图案的缺陷结构，通过重新供应硒可将其恢复为原始的VSe。当沉积的V比Se多时，在Au(111)上发现了一种没有体相类似物的新化合物，在提供过量的Se后它可以转变回VSe。由于V硒化物相的调控实现微妙地取决于V与Se的相对比例以及退火后处理，本报告为深入理解TMDs的生长机制提供了有用的见解，并可能促进VSe在催化和纳米电子学等相关领域的广泛应用。
