Realization of an Electrically Tunable Narrow-Bandwidth Atomically Thin Mirror Using Monolayer MoSe_{2}

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanotechnology

Background:

• Two-dimensional (2D) semiconductors and van der Waals heterostructures are advancing condensed matter physics.
• These materials enable the development of novel devices with unique functionalities.

Purpose of the Study:

• To experimentally demonstrate an electrically tunable, atomically thin mirror using a monolayer of MoSe₂.
• To investigate the optical properties and tunability of this 2D semiconductor-based mirror.

Main Methods:

• Fabrication of a charge-controlled heterostructure incorporating a monolayer of MoSe₂.
• Experimental characterization of the mirror's extinction ratio and reflection coefficient.
• Investigation of reflectivity modulation via applied gate voltage to alter charge density.

Main Results:

• Achieved 87% extinction of incident light resonant with the MoSe₂ exciton transition.
• Obtained a maximum reflection coefficient of 41%, limited by exciton decay rates.
• Demonstrated that reflectivity is independent of incident light intensity up to 400 W/cm².
• Showcased drastic modification of reflectivity by gate voltage-induced changes in charge density.

Conclusions:

• A monolayer of MoSe₂ in a heterostructure functions as an electrically tunable, atomically thin mirror.
• The device exhibits high performance characteristics, including significant extinction and tunable reflectivity.
• Potential applications include fast, programmable spatial light modulators and ultralight mirrors for optomechanical systems.