Chemical vapor deposition and characterization of two-dimensional molybdenum dioxide (MoO₂) nanoplatelets

We report on the chemical vapor deposition synthesis of MoO₂ nanoplatelets by sublimation of MoO₃ and its reduction in a hydrogen atmosphere at 750 °C. When grown on Si/SiO₂ substrates, the platelets primarily assume a rhomboidal shape and have thicknesses ranging from several to tens of nm. The morphology of MoO₂ crystals was found to depend on the chemical nature of substrates. MoO₂ platelets on Si/SiO₂ were characterized by a number of microscopic and spectroscopic techniques, and the electrical measurements revealed the metallic nature of their conductivity averaging at 2400 ± 1000 S cm⁻¹. Raman spectroscopy of MoO₂ platelets on graphene indicates their strong hole injection property. Small thickness, planar morphology, high chemical stability and metallic conductivity of ultrathin MoO₂ platelets make them potentially interesting for integration different other two-dimensional materials in a variety of electronic structures and devices.