Electric Field-Modulated charge transfer in geometrically tailored MoX2/WX2(X = S, Se) heterostructures

Abstract

Light-induced interlayer charge transfer in staggered-type heterostructures (HSs) in transition-metal dichalcogenides provides the opportunity to improve the performance of optoelectronic applications. Herein, we employ density functional theory to investigate the vertical electric-field-controlled interlayer charge transfer in stacked MoX2/WX2 (X=S, Se) HSs. Upon application of electric field from −3 to 3 V/nm, we observe the band-alignment transition, band inversion, and offset variations in these HSs. Furthermore, these electric fields are found to modulate charge localization/delocalization across the layers, which provides insight into charge transfer. The positive electric field is supposed to localize the charges in WS2, whereas the charges are localized in MoS2 at negative electric field. Based on charge localization/delocalization, our study suggests that the interlayer hole transfer upon MoS2 photoexcitation can be suppressed at higher positive electric fields, whereas electron transfer can be blocked by excitation of WS2. In contrast, negative electric fields (of −3 V/nm) can induce interlayer hole and electron transfer. Owing to the tunability of interlayer charge transfer by means of a vertical electric field, our findings bear paramount importance in modulating electron−hole recombination and charge-transfer time, which is beneficial for future optoelectronic devices.