HOME > Profile > MIYATA, Yasumitsu
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- 305-0044 1-1 Namiki Tsukuba Ibaraki JAPAN [Access]
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二次元半導体、遷移金属ダイカルコゲナイド
私たちの研究グループでは、ナノメートルスケールの特徴的な構造を持ち、従来の三次元物質とは異なる特性を示すナノ物質系の研究に取り組んでいます。特に、厚さが原子1〜数個分という極限的に薄い二次元物質に着目し、次世代の半導体デバイスを見据えた基礎研究および応用展開を推進しています。
PublicationsNIMS affiliated publications since 2004.
Research Center for Materials Nanoarchitectonics (MANA)
Title
Structural Engineering and Physical Properties of Transition Metal Dichalcogenides
Keywords
transition metal dichalcogenides, two-dimensional materials, scrolls
Overview
Transition metal dichalcogenide (TMD) nanoscrolls have attracted attention as nanostructures for exploring curvature- and structure-dependent physical properties. In this study, we fabricated diameter-controlled nanoscrolls using vertical heterostructures composed of Janus WSSe, which has different chalcogen elements on its opposite surfaces, and WSe2, and characterized their optical properties.
Novelty and originality
The novelty and originality of this study lie in achieving diameter control of nanoscrolls by combining scrolling driven by the structural asymmetry of Janus WSSe with tuning of the bending rigidity through the number of WSe2 layers. By extending previous approaches based on Janus monolayers to multilayer heterostructures, we controlled nanoscroll diameters over a broad range from approximately 10 nm to 1 μm. Furthermore, we revealed anisotropic Raman responses and strain-induced modulation of second-harmonic generation (SHG), providing new guidelines for controlling the optical properties of TMDs through their three-dimensional structures.
Details
In this study, we fabricated TMD nanoscrolls with different diameters using Janus WSSe/WSe2 heterostructures and investigated their structures and optical properties. First, Janus WSSe was formed by replacing the outermost Se atoms of WSe2 with S atoms through plasma-assisted surface atom substitution. The sheets were subsequently rolled into nanoscrolls through solution treatment. By varying the number of layers in the original sheets, we controlled the nanoscroll diameters over a range of approximately 10 nm to 1 μm. Atomic force microscopy and scanning transmission electron microscopy were used to characterize their morphology and microstructure, confirming uniform crystallinity and composition. Furthermore, polarization-resolved Raman spectroscopy and second-harmonic generation (SHG) measurements revealed anisotropic optical responses and strain-induced modulation of the nonlinear optical response.
Summary
In this study, we controlled nanoscroll diameters over a range of approximately 10 nm to 1 μm by adjusting the number of layers in Janus WSSe/WSe2 heterostructures. We also revealed anisotropic optical responses and strain-induced modulation of SHG. These findings provide a foundation for understanding the relationship between the three-dimensional structures and optical properties of TMDs, paving the way for photonic and optoelectronic applications based on structural control.
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