Preparation and characterization of graphene-based vanadium oxide composite semiconducting films with horizontally aligned nanowire arrays

• VOx-graphene oxide composite (G/VOx) films were fabricated by sol–gel process.
• The G/VOx films mainly consisted of Magnéli-phase VO2 and reduced graphene sheets.
• The G/VOx films exhibited multi-lamellar textures with planar VOx nanowire arrays.
• The G/VOx films showed the thermo-sensitive electrical switching properties.
• Effects of GOs on the electrical characteristics of the G/VOx films were discussed.

Highly oriented crystalline hybrid thin films primarily consisting of Magnéli-phase VO2 and conductive graphene nanoplatelets are fabricated by a sol–gel process via dipping pyrolysis. A combination of chemical, microstructural, and electrical analyses reveals that graphene oxide (GO)-templated vanadium oxide (VOx) nanocomposite films exhibit a vertically stacked multi-lamellar nanostructure consisting of horizontally aligned vanadium oxide nanowire (VNW) arrays along the (hk0) set of planes on a GO template, with an average crystallite size of 41.4 Å and a crystallographic tensile strain of 0.83%. In addition, GO-derived VOx composite semiconducting films, which have an sp3/sp2 bonding ratio of 0.862, display thermally induced electrical switching properties in the temperature range of − 20 °C to 140 °C, with a transition temperature of approximately 65 °C. We ascribe these results to the use of GO sheets, which serve as a morphological growth template as well as an electrochemically tunable platform for enhancing the charge-carrier mobility. Moreover, the experimental studies demonstrate that graphene-based Magnéli-phase VOx composite semiconducting films can be used in advanced thermo-sensitive smart sensing/switching applications because of their outstanding thermo-electrodynamic properties and high surface charge density induced by the planar-type VNWs.