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

Abstract

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.