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An optical spectroscopic study on two-dimensional group-VI transition metal dichalcogenides
1Department of Physics, The Chinese University of Hong Kong, Hong Kong, China.
Chemical Society Reviews
|April 22, 2015
Summary
Atomically thin transition metal dichalcogenides (TMDs) are promising 2D semiconductors for electronics. Their unique valley properties enable valleytronics and quantum manipulation, advancing next-generation devices.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Intensive research focuses on layered materials, especially group-VI transition metal dichalcogenides (TMDs), for atomically thin electronic devices.
- Atomically thin TMD crystals (2H stacking) are intrinsic 2D semiconductors with bandgaps suitable for electronics and optoelectronics.
Purpose of the Study:
- To review recent advances in the optical study of atomically thin group-VI TMDs.
- To highlight their electronic structures, vibrational properties, and excitonic effects.
- To explore the interplay of valley, spin, and layer degrees of freedom for quantum manipulation and valleytronics.
Main Methods:
- Optical studies are employed to investigate electronic structures.
- Analysis of vibrational properties and excitonic effects.
- Examination of valley-dependent optical selection rules and spin-valley coupling.
Main Results:
- Monolayer TMDs exhibit broken inversion symmetry, leading to contrasting Berry curvatures and magnetic moments at K/K' valleys.
- These valleys offer opportunities to control the electron's valley degree of freedom for valleytronics.
- Strong spin-orbit interactions and spin-valley coupling are demonstrated, enabling quantum manipulation.
Conclusions:
- Atomically thin group-VI TMDs are promising candidates for future electronics and optoelectronics.
- Their unique valley and spin properties pave the way for valleytronics and quantum information processing.
- Optical studies are crucial for understanding and harnessing these properties in materials like MoS2, MoSe2, WS2, and WSe2.
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