Effects of solvents and polymer on photoluminescence of transferred WS2 monolayers

Abstract

The poly(methyl methacrylate) (PMMA)-assisted wet transfer is a commonly used method to transfer chemical vapor deposition (CVD)-grown transition metal dichalcogenides (TMDs) onto another substrate. However, the transferred TMDs often show heavy photoluminescence (PL) quenching. This paper evaluates the effects of solvents and polymer involved in the PMMA-assisted wet transfer on the PL intensity of WS2, by systematically exposing CVD-grown WS2 monolayers to solvents and polymer involved during the transfer process. The PL/Raman spectra showed that acetone, IPA, water, and PMMA did not significantly affect the PL characteristics, while KOH caused a heavy PL quenching. The vacuum annealing and acid neutralization removed KOH molecules adsorbed onto WS2. This result warrants further optimization of the PMMA-assisted wet transfer.