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.
