Large-Area Artificial van der Waals “Mille-Feuille” Superlattices

Abstract

Van der Waals heterostructures are set as strong contenders for post-CMOS quantum materials engineering. A major step for their systematic exploration and exploitation of technological component demonstrators resides in their eased large-scale design. In this direction, the growth of artificial van der Waals 2D superlattices is presented here such as (MoS2/WS2)n, (WS2/WSe2)n, and (MoS2/WSe2)n with unit cells repetitions reaching n > 10. The fabrication of these materials is enabled by a fully automated in-situ pulsed laser deposition (PLD) tool. This approach provides cm2 scale homogeneous superlattices with on-demand material parameters tailoring (layer number, order, and composition). The process is rapid and simple compared to manual pickup exfoliation methods or to sequential transfers of single layers grown by techniques such as chemical vapor deposition, allowing a large repetition of the unit cells in a “mille-feuille” cake configuration. The computational exploration of this family of superlattice materials sheds light on the potential for optoelectronic property design by shaping the band-structure landscape while taking into account the influential effects induced by proximity. Overall, this large-area approach is proposed as an entry point for the systematic design of complex van der Waals heterostructures.