Interface and interlayer electron/exciton–phonon coupling of TMDs/InSe for efficient charge transfer and ultrafast dynamics: implications for field-effect devices

Abstract

Transition metal dichalcogenides (TMDs) are potential materials for developing high-performance optoelectronic devices. However, due to the adverse effects of insufficient carrier mobility and limited conductivity, further breakthroughs in optimizing the absorption and transport properties of TMD-based field-effect devices have been hindered. Herein, multifunctional application-based TMD (MX₂: M = Mo, W; X = S, Se)/InSe homo/hetero-heterojunctions are designed for improving absorption and transport properties. In particular, the homo/hetero-heterojunctions and material engineering strategies, charge transfer, and electron mobility of TMDs/InSe have been delved into. The X-ray photoelectron spectroscopy results show type II band alignment and an electron flow from TMDs to InSe in TMDs/InSe heterojunctions. Density functional theory reveals the charge distribution and orbital contribution of TMDs/InSe. TMDs/InSe systems are constructed to form heterojunctions to improve the carrier mobility. The electron mobility of the MoS₂/InSe heterojunction is several times to tens of times compared to that of InSe. The ultrafast carrier dynamics provide a charge transfer channel that increases the carrier lifetime. Under the modulation of light and electric fields, MS₂/InSe field-effect devices exhibit an absorption rate of up to 70–80% and enhanced conductivity. This research will provide useful guidance for the design and optimization of field-effect devices based on TMDs/InSe heterojunctions.