Electrodeposited n-type cuprous oxide cubic nanostructures for liquefied petroleum gas sensing

A surfactant free template assisted electrodeposition method was used to fabricate thick n-type Cu2O films having cubic nanostructures for the detection of liquefied petroleum (LP) gas at low concentrations. Templates were fabricated by initially electrodepositing a p-type Cu2O thin film on a Ti substrate followed by annealing that changed conductivity type of the film, as confirmed by Mott-Schottky and spectral response measurements. SEM measurements of resulting films showed nano-cubic crystals having sizes of 150-300nm. When exposed to a mixture of LP gas and dry air, the resistance of these films increased and the maximum response was recorded when films were maintained at 180 degrees C for all concentrations and it was independent of the surface morphology. At 180 degrees C, at the lowest tested LP gas concentration of 2vol.%, a twofold increase in response was observed in the nano-cubic films compared to the micro-crystalline n-type Cu2O films. This improvement in gas response is attributed to increased effective surface area of these nanostructured films. Compared to other LP gas sensing materials, Cu2O films showed very good response times and recovery times of approximate to 120 and approximate to 90s, respectively.