Epitaxial growth of <010>-oriented MoO2 nanorods on m-sapphire

Molybdenum dioxide (MoO 2 ) materials have attracted considerable interests due to their superduper properties and potential applications, relating to the growth directions and exposed surfaces. Here, we reported as the substrate changes from c-to m-sapphire, the growth direction of epitaxial MoO 2 nanorods via an atmospheric pressure chemical vapor deposition approach changes along from <001> to <010> of bulk monoclinic MoO 2 accompanied by exposing different surfaces. Optical microscopy (OM), Raman spectroscopy , X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), cross-sectional scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED) measurements reveal these MoO 2 nanorods are epitaxially grown on m-sapphire substrates with the orientation of MoO 2 (101)//sapphire ( 10 1 ‾ 0 ) and MoO 2 <010> in line with sapphire <0001>. The electrical conductivity significantly depends on the crystallographic direction of MoO 2 nanorods . The method to control the growth directions of 1D MoO 2 nanorods has potential applications in nanoelectronic devices.