Facile photothermal synthesis of localized vanadium oxide capable of extraordinary phase transition

We demonstrate the in situ localized synthesis of vanadium oxides on glass and plastic substrates using localized laser illumination. The proposed technique is efficient and simple in terms of thermal budget and fabrication complexity. The physical properties of the laser-induced vanadium oxide channel region, which is mainly composed of VO2 and V2O5, are assessed by Raman analysis, while its electrical properties and phase transition characteristics with respect to the input optical powers and voltage biases are carefully examined by various resistance measurements. At a bias voltage of the order of 1 V, for example, optically triggered irreversible resistance switching through insulator-to-metal transition of vanadium oxide materials can be observed. The resistance switching ratio before and after the temperature-dependent phase transition exceeds two orders of magnitude. The obtained results confirm the applicability of the photothermally fabricated vanadium oxide devices to illumination-based resistance switching and temperature-dependent current flow management with large dynamic ranges. The proposed fabrication technique can also be applied to other transition metal oxide materials, which are currently grown at high temperatures or vacuum environments, for flexible electronics applications.