Synthesis of biaxial MgO/Mg–Sn–O nanowire heterostructures and their structural and luminescence properties

Biaxial MgO/magnesium tin oxide (MTO) heterostructure nanowires were synthesized using a single thermal evaporation process. An epitaxial relationship of (2 2 0)MgO∥(2 2 0)MTO was observed at the interface between the MgO and MTO sub-layers in the biaxial MgO/MTO heterostructure nanowires. The MgO sublayer contained mainly MgO and MgO2 phases, whereas the MTO sublayer consisted of Mg2SnO4 and SnO2 phases as well as MgO and MgO2 phases. The biaxial nanowire growth process involved two dominant steps: MgO nanowire growth by a vapor–liquid–solid (VLS) mechanism and epitaxial MTO sublayer growth on the pregrown MgO nanowire. The biaxial MgO/MTO nanowires showed an emission bands at ∼440 nm and ∼470 nm in the bluish violet and blue regions, respectively, whereas pure MgO nanowires showed an emission band at ∼510 nm in the blue/green region. The emission intensity of the former was considerably stronger than those of the latter.

► Biaxial MgO/MTO heterostructure nanowires were synthesized using a single thermal evaporation process.
► An epitaxial relationship of (2 2 0)MgO∥(2 2 0)MTO was observed in the biaxial nanowires.
► The emission intensity of the biaxial nanowires was considerably stronger than those of MgO nanowires.