Homogeneous surface oxidation and triangle patterning of monolayer MoS2 by hydrogen peroxide

Abstract Atomically thin monolayer molybdenum disulfides (MoS 2 ) with tunable electronic structure has promising applications in opto-electronic devices and sensors. In this work, unique nano-patterning and surface oxidation of monolayer MoS 2 was achieved based on hydrogen peroxide (H 2 O 2 ) treatment. It was found that the exfoliated monolayer MoS 2 can be uniformly oxidized when exposed to low-concentration H 2 O 2 , forming an intermediate phase composed of MoS x O y . In addition, patterned triangular pits with well-defined edges can be formed under high-concentration H 2 O 2 condition. The band gap of monolayer MoS 2 could be effectively modulated by H 2 O 2 treatment as verified by photoluminescence spectra. This work shows that simple H 2 O 2 treatment can be an alternative approach for both surface functionalization and band gap modulation of MoS 2 flake, and it also provides an alternatively simple way to obtain patterned MoS 2 nanostructures without complicated standard lithography processes.