EpitaxialSynthesis of Monolayer PtSe 2 SingleCrystal on MoSe 2 with Strong Interlayer Coupling

PtSe2, a new layered two-dimensional material, has drawn intensive attention owing to its layer-dependent band structure, high air stability and spin-layer locking effect which embraces the applications for next-generation optoelectronic, electronic devices and catalysis. However, synthesis of large monolayer PtSe2 single crystal is challenging due to the low chemical reactivity of Pt sources. Here, we report the synthesis of monolayer PtSe2 single crystal via epitaxy growth on MoSe2 by a one-step chemical vapor deposition (CVD) method. The underlying MoSe2 substrate plays a key role for the monolayer growth of PtSe2. The periodic Moire patterns from the vertically stacked heterostructure (PtSe2/MoSe2) are clearly identified via annular dark-field scanning transition electron microscopy (ADF-STEM). First-principles calculations show a type-II band alignment and reveal interface states originating from the Strong-Weak Interlayer Coupling (S-WIC) between PtSe2 and MoSe2 monolayers, as demonstrated by the el...