Anisotropic MoS₂ Nanosheets Grown on Self-Organized Nanopatterned Substrates

Area of Science:

• Materials Science
• Nanotechnology
• Condensed Matter Physics

Background:

• Tailoring anisotropy in 2D nanosheets is key to controlling nanoscale functional properties.
• Molybdenum disulfide (MoS2) is a prominent 2D material with diverse applications.

Purpose of the Study:

• To develop a novel method for inducing one-directional anisotropy in MoS2 nanosheets.
• To investigate the impact of this induced anisotropy on MoS2's optoelectronic and phonon properties.

Main Methods:

• Chemical vapor deposition (CVD) of MoS2 onto ion-sputtered SiO2/Si substrates with pre-patterned ripples.
• Analysis of anisotropic phonon modes and their dependence on polarization orientation relative to ripple axis.
• Investigation of nanoscale strain localization and charge doping effects induced by the rippled morphology.

Main Results:

• Successfully introduced one-directional anisotropy in MoS2 nanosheets via substrate pattern engineering.
• Observed strongly anisotropic phonon modes, sensitive to polarization relative to the ripple axis.
• Demonstrated topography-dependent modulation of MoS2 workfunction and substantial redshifts in phonon frequencies due to strain and doping.

Conclusions:

• The rippled substrate pattern effectively controls anisotropy in CVD-grown MoS2 nanosheets.
• Induced anisotropy significantly alters optoelectronic and phonon properties, offering tunable nanoscale functionalities.
• This approach provides a pathway for controllable anisotropy engineering in 2D materials via substrate design.