Monolayer Semiconductor Devices [BPN694]
In this work, we report lateral heterojunction formation in as-exfoliated MoS2 flakes by
thickness modulation. Kelvin probe force microscopy is used to map the surface potential at the
monolayer-multilayer heterojunction, and consequently the conduction band offset is extracted.
Scanning photocurrent microscopy is performed to investigate the spatial photocurrent response
along the length of the device including the source and the drain contacts as well as the
monolayer-multilayer junction. The peak photocurrent is measured at the monolayer-multilayer
interface, which is attributed to the formation of a type-I heterojunction. The work presents
experimental and theoretical understanding of the band alignment and photoresponse of thickness
modulated MoS2 junctions with important implications for exploring novel optoelectronic devices.