摘要
Two-dimensional(2D)vertically stacked heterostructures based on layered transition-metal dichalcogenides(MDCs)have remarkablepote ntial in future applications due to their rich in terlayer related properties,such as in terlayer excitons,tun able interlayer band alignments.However,the controlled growth of TMDC bilayer heterostructures with preferred stacking structure remains challenging.Here,we report atwo-step van der Waals epitaxial vapor growth of WSe2/WS2 vertically stacked bilayer heterostructures with controllable commensurate crystallographic alignments(so called AA and AB stacki ng),by controlling the deposition temperature.Moire patter ns were obtai ned in bothAA and AB stacked WSe2/WS2 heterostructures.The stacking configuration of the vertical heterostructures was verified by the secondharmonic generation signals.Photoluminescenee and Raman spectroscopy studies further confirm that the heterostructures with differentstacking configuration have obviously different optical properties,which is ascribed to the distinct in terlayer coupling and resonance excitation between the distinguishing AA and AB stacked heterostructures.The controlled growth of AA and AB stacked heterostructures could provide an importa nee platform not only for fun dame ntal researches but also for functional electronic and optoelectronic deviceapplications.
基金
The authors are grateful to the National Natural Science Foundation of China(Nos.51525202,51772084,91850116,51802089,61574054,and 61635001)
Innovation platform and talent plan of Hunan Province(No.2017RS3027)
the Hunan Province Science and Technology Plan(No.2019JJ50048)
the Program for Youth Leading Talent and Science and Technology Innovation of Ministry of Science and Technology of China,the Fundamental Research Funds for the Central Universities,and the Foundation for Innovative Research Groups of NSFC(No.21521063).
