Epitaxial Growth of Highly Oriented Metallic MoO2@MoS2 Nanorods on C-sapphire

Molybdenum dioxide (MoO2) has attracted many interests due to its unique properties and potential applications. Here, we report the synthesis of high quality MoO2@MoS2 nanorods on c-sapphire substrates through an atmospheric pressure chemical vapor deposition (APCVD) approach. Optical microscopy (OM), cross-sectional scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), and (grazing incidence) X-ray diffraction ((GI)XRD) measurements reveal that these MoO2 nanorods exhibit epitaxial growth behaviors on c-sapphire substrates with the orientation relationship of MoO2(100)∥sapphire(0001) and MoO2 ⟨001⟩ aligned well with sapphire ⟨101̅0⟩. Raman spectroscopy/imaging, energy dispersive spectroscopy (EDS), and GIXRD results disclose that such MoO2 nanorods are wrapped by MoS2 (MoO2@MoS2). Devices based on transferred individual MoO2@MoS2 nanorods show a resistivity of ∼1.65 × 10–4 Ω·cm, comfirming that such nanorods possess higher crystalline degree. Our findings will be helpful for the applications of MoO2@MoS2 in the fields of nanoelectronic devices.