Rapid hydrogenation of VO2 thin films via metal-acid contact method using mild electric fields at room temperature

•Hydrogenation of VO2 thin films via metal-acid contact method under mild electric fields.•Rapid hydrogenation at room temperature just in 30 s.•High reversibility and sustainability of the films even after several cycles of hydrogenation and dehydrogenation. Five thin films of VO2 were grown on single-crystal sapphire substrates in identical deposition conditions using pulsed excimer laser with an objective to study hydrogenation under different electric fields at room temperature. For hydrogenation, a self-made steup was used with the provision of the negative (film) and positive electrodes in acidic solution. The microstructural, crystallographic and electrical properties were studied in detail. By applying only a trivial voltage of 0.001 mV at 3 cm distance for hydrogenation just for 30 s, the resistivity of the film decreased by one order of magnitude at room temperature, indicating incorporation of a good amount of hydrogen in VO2. We find that the hydrogenation is not only sustainable and reversible but a lot more rapid as compared to other techniques.