[14p-A33-1~15] Trend of Functional Atomic Thin Film Research-Thin Film Growth-

△ [14p-A33-12] Synthesis of MoS₂ and MoSe₂ on Au(111) and the Local Electronic State Analysis

〇Ryosuke Takahashi¹, Ryo Osaka¹, Satoshi Yasuda¹, Kei Murakoshi¹ (1.Hokkaido Univ.)

Keywords:transition metal dichalcogenide, Raman spectroscopy, scanning tunneling microscopy

We have found that local densities of states were introduced in the band gaps of MoS₂ and MoSe₂ monolayers grown by chemical vapor deposition on Au(111) surfaces. Raman spectroscopic analysis indicated a splitting of out-of-plane A_1g Raman modes of both MoS₂ and MoSe₂ layers on Au(111) surfaces, whereas no splitting was observed on polycrystalline Au or SiO₂/Si surfaces. These results demonstrated that contact with a crystalline Au(111) surface gives rise to out-of-plane strain in both MoS₂ and MoSe₂ layers. STM analysis provided 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 moiré superstructure formation for MoS₂ and MoSe₂ layers on Au(111). This observation indicates that the adsorption sites of the Au(111) surface interact with MoS₂ or MoSe₂ layers, giving rise to out-of-plane strain in the layers. This leads to effective modulation of the local electronic structure of the MoS₂ or MoSe₂ layer, introducing characteristic electronic states in the bandgap. The present system provides a novel possibility of controlling the electronic and phonon structures via periodic surface strain induced by relatively weak interactions (van der Waals forces) between single-atomic-layer materials and single-crystalline metal surfaces.