Dielectric screening effect on exciton resonance energy in monolayer WS2 on SiO2/Si substrate

Abstract

We studied the dielectric screening effects by a SiO2/Si substrate on the excitonic properties of monolayer WS2 by means of microscopic reflectance and photoluminescence spectroscopy. Through the observation of high-order exciton resonances from 1s to 5s at 10 K, we estimated the band gap and exciton binding energy. Our theoretical calculation using the screened Keldysh potential well reproduced the high-order Rydberg energies. In addition, we discussed the deviation of oscillator strength obtained from experimental results in comparison with theoretical calculation.