Stark effect spectroscopy of mono- and few-layer MoS${}_2$

Abstract

We demonstrate electrical control of the A-exciton interband transition in mono- and few-layer $Mo{S}_2$ crystals embedded into photocapacitor devices via the DC Stark effect. Electric field dependent low-temperature photoluminescence spectroscopy reveals a significant tuneability of the A-exciton transition energy, up to $\sim 16meV$, from which we extract the mean DC exciton polarisability $<{\bar{\hat{I}}}^2{>}_N=(0.58\pm 0.25)\cdot 10^{-8}Dm{V}^{-1}$. The exciton polarisability is shown to be layer-independent, indicating a strong localisation of both electron and hole wave functions in each individual layer.

19 pages, 4 figures in Nano Lett. 2016