Epitaxial Growth of Two-Dimensional MoO2–MoSe2 Metal–Semiconductor Heterostructures for Schottky Diodes

The metal-semiconductor interface fabricated by conventional methods often suffers from contamination, degrading transport performance. Herein, we propose a one-pot chemical vapor deposition (CVD) process to create a two-dimensional (2D) MoO₂-MoSe₂ heterostructure by growing MoO₂ seeds under a hydrogen environment, followed by depositing MoSe₂ on the surface and periphery. The ultraclean interface is verified by cross-sectional scanning transmission electron microscopy and photoluminescence. Along with the high work function of semimetallic MoO₂ (E_f = -5.6 eV), a high-rectification Schottky diode is fabricated based on this heterostructure. Furthermore, the Schottky diode exhibits an excellent photovoltaic effect with a high open-circuit voltage of 0.26 eV and ultrafast photoresponse, owing to the naturally formed metal-semiconductor contact with suppressed pinning effect. Our method paves the way for the fabrication of an ultraclean 2D metal-semiconductor interface, without defects or contamination, offering promising prospects for future nanoelectronics.