Linear quantum-confined Stark effect and field tunable excitonic oscillator strength in bilayer WS<sub>2</sub>

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APS March Meeting 2021

Volume 66, Number 1

Monday–Friday, March 15–19, 2021; Virtual; Time Zone: Central Daylight Time, USA

Session J31: Hybrid Quantum Systems II - Optomechanics

3:00 PM–6:00 PM, Tuesday, March 16, 2021

Sponsoring Unit: DQI
Chair: Gerwin Koolstra, Lawrence Berkeley National Laboratory

Abstract: J31.00001 : Linear quantum-confined Stark effect and field tunable excitonic oscillator strength in bilayer WS₂

3:00 PM–3:12 PM Live

Abstract

Presenter:

Sarthak Das
(Electrical Communication Engineering, Indian Institute of Science Bangalore)

Authors:

Sarthak Das
(Electrical Communication Engineering, Indian Institute of Science Bangalore)

Medha Dandu
(Electrical Communication Engineering, Indian Institute of Science Bangalore)

Garima Gupta
(Electrical Communication Engineering, Indian Institute of Science Bangalore)

Krishna Murali
(Electrical Communication Engineering, Indian Institute of Science Bangalore)

Nithin Abraham
(Electrical Communication Engineering, Indian Institute of Science Bangalore)

Takashi Taniguchi
(International Center for Materials Nanoarchitectonics, National Institute for Materials Science)

Kenji Watanabe
(Research Center for Functional Materials, National Institute for Materials Science)

Sangeeth Kallatt
(Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Denmark)

Kausik Majumdar
(Electrical Communication Engineering, Indian Institute of Science Bangalore)

The reflection symmetry is broken while the inversion symmetry is restored in bilayer TMDs unlike monolayers¹. This results in anomalous field-dependent excitonic behavior in bilayer WS₂ compared with monolayers. First, we show a linear quantum-confined Stark effect of bilayer intra-layer excitons with a vertical electric field, contrary to a quadratic one for a monolayer. Second, we demonstrate a strong field-dependent tunability of the oscillator strength of the intra-layer exciton due to a partial interconversion from intra-layer to inter-layer character with an increase in the vertical field. Third, using a modified device structure, we also show an efficient modulation of the excitonic response by transferring the oscillator strength from exciton to trion via electrostatic doping. These demonstrations make bilayer WS₂ as an excellent candidate for the field tunable ultrathin electro-optical absorption modulator² at the exciton resonance. These observations can find applications in various domains ranging from novel photonic devices, optical modulators, optical computing to imaging, and on-chip reconfigurable compact devices for next-generation optoelectronics.
References:
1. Das, S., et al. Phys. Rev. B 2019, 99, 165411.
2. Scuri, G., et al. Phys. Rev. Lett. 2018, 120, 037402.

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Bulletin of the American Physical Society

APS March Meeting 2021

Volume 66, Number 1

Monday–Friday, March 15–19, 2021; Virtual; Time Zone: Central Daylight Time, USA

Session J31: Hybrid Quantum Systems II - Optomechanics

Abstract: J31.00001 : Linear quantum-confined Stark effect and field tunable excitonic oscillator strength in bilayer WS2

Presenter:

Authors:

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Abstract: J31.00001 : Linear quantum-confined Stark effect and field tunable excitonic oscillator strength in bilayer WS₂