In-Plane Electric Field Induced Orbital Hybridization of Excitonic States In Monolayer WSe2

TL;DR

This study demonstrates how an in-plane electric field can induce orbital hybridization of excitonic states in monolayer WSe2, enabling control over exciton properties for potential electro-optical applications.

Contribution

It reveals electric field-induced orbital hybridization of excitonic states and enhances oscillator strength, advancing understanding of exciton manipulation in 2D materials.

Findings

Electric field causes hybridization of 2s and 2p excitonic states.

Electric field increases oscillator strength of excited excitons.

Electric field enables control of excitonic states for optoelectronic applications.

Abstract

The giant exciton binding energy and the richness of degrees of freedom make monolayer transition metal dichalcogenide an unprecedented playground for exploring exciton physics in 2D systems. Thanks to the well energetically separated excitonic states, the response of the discrete excitonic states to the electric field could be precisely examined. Here we utilize the photocurrent spectroscopy to probe excitonic states under a static in-plane electric field. We demonstrate that the in-plane electric field leads to a significant orbital hybridization of Rydberg excitonic states with different angular momentum (especially orbital hybridization of 2s and 2p) and consequently optically actives 2p-state exciton. Besides, the electric-field controlled mixing of the high lying exciton state and continuum band enhances the oscillator strength of the discrete excited exciton states. This electric field modulation of the excitonic states in monolayer TMDs provides a paradigm of the manipulation of 2D excitons for potential applications of the electro-optical modulation in 2D semiconductors.