Electrochemistry of CuO/In2O3 p-n heterojunction nano/microstructure array with sensitivity to H2 at and below room-temperature

We report a facile template-free procedure to synthesize CuO/In2O3 p-n heterojunction nano/microstructure array on Si substrate. It was synthesized by electrodeposition in quasi-2D ultra-thin liquid layer combining with annealing treatment. By applying a special square potential across the electrodes, Cu2+ and In3+ were selectively and periodically deposited according to their reduction potentials. The array is well-ordered with strictly periodic arrangement in hundreds of microns, and it shows a reasonable sensitivity and selectivity to H-2 at and below room temperature due to the tunneling modulation of heterojunction array. And the mechanisms of electrodeposition and tunneling modulation obtained rational explanation. (C) 2013 Elsevier B.V. All rights reserved.