Delocalization and bandgap engineering in defective MoS2 by metal-ion doping for enhanced electrical performance and efficient near-infrared detection

Abstract

This study presents delocalization and bandgap engineering in defective MoS2 by metal-ion doping. Due to inevitable defects, MoS2 field-effect transistors (FETs) exhibit unstable electrical characteristics. However, doping with indium, gallium, zinc, and oxygen ions using an IGZO layer enhances the stability and electrical performance of the MoS2 FETs, and remarkably enables efficient detection of near-infrared light. Chemical and structural analyses show that the metal ions diffuse into defective MoS2, forming a few-nanometer-thick doped MoS2 with a delocalized and reduced electronic structure, and also a quasi-quantum well structure of MoS2, doped MoS2, and IGZO. Current–voltage analyses and ab initio density functional theory calculations reveal that, due to the delocalized doped layer and the quasi-quantum-well structure, charge transport is confined to the layer, leading to remarkable near-infrared detection properties and band-like charge transport. We thus regard the doping-induced delocalization and bandgap engineering in defective MoS2 as promising for next-generation optoelectronic applications.