Stark effect spectroscopy of mono- and few-layer MoS$_{2}$

TL;DR

This study demonstrates electrical tuning of exciton transition energies in mono- and few-layer MoS₂ using the DC Stark effect, revealing layer-independent exciton polarizability and potential for optoelectronic applications.

Contribution

It provides the first detailed measurement of exciton polarizability in layered MoS₂ and shows layer independence, advancing understanding of excitonic properties under electric fields.

Findings

Achieved up to 16 meV tuning of exciton energy

Measured exciton polarizability of (0.58 ± 0.25) × 10^{-8} DmV^{-1}

Found exciton polarizability to be layer-independent

Abstract

We demonstrate electrical control of the A-exciton interband transition in mono- and few-layer $MoS_{2}$ 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 $\sim 16 meV$, from which we extract the mean DC exciton polarisability $<\bar{\beta}>_{N} = (0.58 \pm 0.25) \cdot 10^{-8} DmV^{-1}$. The exciton polarisability is shown to be layer-independent, indicating a strong localisation of both electron and hole wave functions in each individual layer.