The role of interface traps to affect monolayer MoS₂ phototransistor

With high quantum efficiency, layer-dependent bandgap, and minimal dark current, molybdenum disulfide (MoS₂) phototransistors show promise in scientific research and practical applications. The atomic layer thickness of monolayer MoS₂ on silicon dioxide (SiO₂) significantly influences properties such as mobility and carrier concentration due to interfacial traps. These traps lead to an increase in dark current, thus reducing photo-detectivity and sensitivity in MoS₂-based photodetectors. In this study, we explore a MoS₂-based field-effect phototransistor with interfacial trap effects at the MoS₂/SiO₂ and Si/SiO₂ interfaces. Varying source-drain voltage, gate voltage, and illumination power, we examine the impact of interface traps. Our results reveal the emergence of an optically induced field (OIF) during illumination, originating from the interaction between photon-generated electrons and interfacial traps. OIF significantly influences both strength and direction of photocurrent. These findings provide a novel approach to studying interface traps in ultrathin material phototransistors, contributing to advancements in this field.