Narrow photoluminescence peak of epitaxial MoS${}_2$ on graphene/Ir(111)

Abstract

We report on the observation of photoluminescence (PL) with a narrow 18 meV peak width from molecular beam epitaxy grown MoS${}_2$ on graphene/Ir(111). This observation is explained in terms of a weak graphene-MoS${}_2$ interaction that prevents PL quenching expected for a metallic substrate. The weak interaction of MoS${}_2$ with the graphene is highlighted by angle-resolved photoemission spectroscopy and temperature dependent Raman spectroscopy. These methods reveal that there is no hybridization between electronic states of graphene and MoS${}_2$ and a different thermal expansion of graphene and MoS${}_2$. Molecular beam epitaxy grown MoS2 on graphene is therefore an important platform for optoelectronics which allows for large area growth with controlled properties.

18 pages, 5 figures, submitted for review