Optical fingerprint of non-covalently functionalized transition metal dichalcogenides
Artikel i vetenskaplig tidskrift, 2017

Atomically thin transition metal dichalcogenides (TMDs) hold promising potential forapplications in optoelectronics. Due to their direct band gap and the extraordinarily strong Coulomb interaction, TMDs exhibit efficient light-matter coupling and tightly bound excitons. Moreover, large spin orbit coupling in combination with circular dichroism allows for spin and valley selective optical excitation. As atomically thin materials, they are very sensitive to changes in the surrounding environment. This motivates a functionalization approach, where external molecules are adsorbed to the materials surface to tailor its optical properties. Here, we apply the density matrix theory to investigate the potential of non-covalently functionalized monolayer TMDs. Considering exemplary molecules with a strong dipole moment, we predict spectral redshifts and the appearance of an additional side peak in the absorption spectrum of functionalized TMDs. We show that the molecular characteristics, e.g. coverage, orientation and dipole moment, crucially influence the optical properties of TMDs, leaving a unique optical fingerprint in the absorption spectrum. Furthermore, we find that the molecular dipole moments open a channel for coherent intervalley coupling between the high-symmetry K and K' points which may create new possibilities for spin-valleytronics application.

Disulfide

functionalization

excitonic absorption spectrum

Spectroscopy

Graphene

transition metal dichalcogenides

Författare

Maja Feierabend

Chalmers, Fysik, Kondenserade materiens teori

Ermin Malic

Chalmers, Fysik, Kondenserade materiens teori

A. Knorr

Gunnar Berghäuser

Chalmers, Fysik, Kondenserade materiens teori

Journal of Physics Condensed Matter

0953-8984 (ISSN)

Vol. 29 38 Article no 384003 -

Ämneskategorier

Fysik

DOI

10.1088/1361-648X/aa7eb3

Mer information

Skapat

2017-10-08