Room Temperature, Twist Angle Independent, Momentum Direct Interlayer Excitons in van der Waals Heterostructures with Wide Spectral Tunability

Poudyal, S and Deka, M and Adhikary, P and Ranju, D and Barman, PK and Yadav, R and Biswal, B and Rajarapu, R and Mukherjee, S and Nanda, BRK and Singh, A and Misra, A (2024) Room Temperature, Twist Angle Independent, Momentum Direct Interlayer Excitons in van der Waals Heterostructures with Wide Spectral Tunability. In: Nano Letters, 24 (31). 9575 -9582.

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Abstract

Interlayer excitons (IXs) in van der Waals heterostructures with static out of plane dipole moment and long lifetime show promise in the development of exciton based optoelectronic devices and the exploration of many body physics. However, these IXs are not always observed, as the emission is very sensitive to lattice mismatch and twist angle between the constituent materials. Moreover, their emission intensity is very weak compared to that of corresponding intralayer excitons at room temperature. Here we report the room-temperature realization of twist angle independent momentum direct IX in the heterostructures of bulk PbI2 and bilayer WS2. Momentum conserving transitions combined with the large band offsets between the constituent materials enable intense IX emission at room temperature. A long lifetime (�100 ns), noticeable Stark shift, and tunability of IX emission from 1.70 to 1.45 eV by varying the number of WS2 layers make these heterostructures promising to develop room temperature exciton based optoelectronic devices. © 2024 American Chemical Society.

Item Type:	Journal Article
Publication:	Nano Letters
Publisher:	American Chemical Society
Additional Information:	The copyright for this article belongs to publisher.
Keywords:	Iodine compounds; Lattice mismatch; Layered semiconductors; Lead compounds; Molybdenum compounds; Momentum; Optoelectronic devices; Semiconductor quantum wells; Transition metals; Tungsten compounds; Van der Waals forces, Angle-independent; Dichalcogenides; Interlayer exciton; Long lifetime; Optoelectronics devices; Spectral tunability; Transition metal dichalcogenides; Twist angles; Van der Waal; Van der waal heterostructure, Excitons
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	10 Oct 2024 09:53
Last Modified:	10 Oct 2024 09:53
URI:	http://eprints.iisc.ac.in/id/eprint/86419

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