Design and build MoS2/Au/MoS2 sandwich structure to significantly enhance the photoluminescence

Usually the bi-layer MoS2 grown directly by chemical vapor deposition or exfoliated by mechanical method has an indirect band gap, which leads to poor optical property. In this work, we design and build the sandwich structure by stacking a bi-layer MoS2 with Au nanoparticles embedded in the adjacent layers. This structure shows a 45-fold enhancement in photoluminescence (PL) compared with the direct grown bi-layer MoS2. More importantly, the as-built bi-layer MoS2 area shows much stronger in the PL intensity than that of the monolayer MoS2 area. This work presents the optimized PL enhancement of this homogeneous MoS2 structure by the surface plasmon resonance (SPR) effect of the Au nanoparticles and the effect of direct bandgap bi-layer MoS2 structures via tuning the interlayer distance between the adjacent MoS2 layers.