Observation of Inter-layer Excitons in MoSe2 Single Crystals

TL;DR

This study reports the observation and analysis of interlayer excitons in MoSe2 single crystals, revealing their properties and potential for high-temperature dipolar exciton applications.

Contribution

First unambiguous identification and characterization of interlayer excitons in MoSe2 using spectroscopy and theoretical analysis.

Findings

Interlayer excitons coexist with intralayer excitons in MoSe2.

Interlayer excitons have a binding energy of 153 meV and narrow linewidth.

Interlayer excitons exhibit distinct transition energies and dipole moments.

Abstract

Interlayer excitons are observed coexisting with intralayer excitons in bi-layer, few-layer, and bulk MoSe2 single crystals by confocal reflection contrast spectroscopy. Quantitative analysis using the Dirac-Bloch-Equations provides unambiguous state assignment of all the measured resonances. The interlayer excitons in bilayer MoSe2 have a large binding energy of 153 meV, narrow linewidth of 20 meV, and their spectral weight is comparable to the commonly studied higher-order intralayer excitons. At the same time, the interlayer excitons are characterized by distinct transition energies and permanent dipole moments providing a promising high temperature and optically accessible platform for dipolar exciton physics.