Controlling structure and interfacial interaction of monolayer TaSe2 on bilayer graphene

TL;DR

This study demonstrates controlled epitaxial growth of monolayer TaSe2 with different phases on bilayer graphene, revealing how structural variations influence interfacial electronic interactions, which is vital for designing tailored 2D heterostructures.

Contribution

It introduces a method for phase-controlled epitaxial growth of TaSe2 on graphene, enabling tunable interfacial interactions for 2D heterostructure engineering.

Findings

1H-TaSe2 shows strong charge transfer and band hybridization.

1T-TaSe2 exhibits weak substrate interactions.

Interfacial effects depend on work function differences and interlayer distance.

Abstract

Tunability of interfacial effects between two-dimensional (2D) crystals is crucial not only for understanding the intrinsic properties of each system, but also for designing electronic devices based on ultra-thin heterostructures. A prerequisite of such heterostructure engineering is the availability of 2D crystals with different degrees of interfacial interactions. In this work, we report a controlled epitaxial growth of monolayer TaSe2 with different structural phases, 1H and 1T, on a bilayer graphene (BLG) substrate using molecular beam epitaxy, and its impact on the electronic properties of the heterostructures using angle-resolved photoemission spectroscopy. 1H-TaSe2 exhibits significant charge transfer and band hybridization at the interface, whereas 1T-TaSe2 shows weak interactions with the substrate. The distinct interfacial interactions are attributed to the dual effects from the differences of the work functions as well as the relative interlayer distance between TaSe2 films and BLG substrate. The method demonstrated here provides a viable route towards interface engineering in a variety of transition-metal dichalcogenides that can be applied to future nano-devices with designed electronic properties.