Out-of-plane strain induced in a Moir superstructure of monolayer MoS and MoSe on Au(111)

Yasuda, Satoshi   ; Takahashi, Ryosuke*; Osaka, Ryo*; Kumagai, Ryota*; Miyata, Yasumitsu*; Okada, Susumu*; Hayamizu, Yuhei*; Murakoshi, Kei*

MoS and MoSe monolayers are grown on Au surface by chemical vapor deposition and it is demonstrated that the contact with a crystalline Au(111) surface gives rise to only out-of-plane strain in both MoS and MoSe layers, whereas no strain generation is observed on polycrystalline Au or SiO/Si surfaces. Scanning tunneling microscopy analysis provides information regarding consequent specific adsorption sites between lower S (Se) atoms in the S-Mo-S (Se-Mo-Se) structure and Au atoms via unique moir superstructure formation for MoS and MoSe layers on Au(111). This observation indicates that the specific adsorption sites give rise to out-of-plane strain in the TMDC layers. Furthermore, it also leads to effective modulation of the electronic structure of the MoS or MoSe layer.