Electronic growth of Ag islands on MoS₂

Abstract

Molybdenum disulfide (MoS2) are emerging as an attractive material for next-generation electronics. Therefore, the growth of metals on MoS2 is of importance for future technologies. We used scanning tunneling microscopy to study the growth of Ag on MoS2. It was found that flat Ag islands with (111) surfaces and steep edges can be formed on MoS2 without a wetting layer. In particular, islands prefer to have thickness of six atomic layers at a low coverage. The manifestation of preferred thickness implies that the formation of Ag islands follows the electronic growth driven by the quantum size effect. Moreover, we annealed Ag islands to observe their thermal stability. We found that most of the Ag islands have thickness of 11 atomic layers after annealing, revealing another preferred thickness. This result implies that the applied thermal energy is insufficient for overriding the quantum size effect, although it can induce the reformation of Ag islands.