Microlandscaping of Au nanoparticles on few-layer MoS2 films for chemical sensing

Surface modification or decoration of ultrathin MoS2 films with chemical moieties is appealing since nanointerfacing can functionalize MoS2 films with bonus potentials. In this work, a facile and effective method for microlandscaping of Au nanoparticles (NPs) on few-layer MoS2 films is developed. This approach first employs a focused laser beam to premodify the MoS2 films to achieve active surface domains with unbound sulfur. When the activated surface is subsequently immersed in AuCl3 solution, Au NPs are found to preferentially decorate onto the modified regions. As a result, Au NPs can be selectively and locally anchored onto designated regions on the MoS2 surface. With a scanning laser beam, microlandscapes comprising of Au NPs decorated on laser-defined micropatterns are constructed. By varying the laser power, reaction time and thickness of the MoS2 films, the size and density of the NPs can be controlled. The resulting hybrid materials are demonstrated as efficient Raman active surfaces for the detection of aromatic molecules with high sensitivity.