Photoluminescence and charge transfer in the prototypical 2D/3D semiconductor heterostructure MoS₂/GaAs

The new generation of two-dimensional (2D) materials has shown a broad range applications for optical and electronic devices. Understanding the properties these when integrated with more traditional three-dimensional (3D) semiconductors is an important challenge implementation ultra-thin Recent observations have that by combining MoS$_2$ GaAs it possible to develop high quality photodetectors solar cells. Here, we present study effects intrinsic GaAs, p-doped n-doped substrates on photoluminescence monolayer MoS$_2$. We observe decrease order magnitude in emission intensity all MoS$_2$/GaAs heterojunctions, compared control sample consisting isolated from few layers hexagonal boron nitride. also see dependence trion A-exciton ratio spectra type substrate, relate static charge exchange between junction formed. Scanning Kelvin probe microscopy measurements heterojunctions suggest type-I band alignments, so excitons generated will be transferred substrate. Our results shed light leading offsets 2D/3D which play central role understanding further improvement