Synthesis and photoelectric characterization of delafossite conducting oxides CuAlO2 laminar crystal thin films via sol–gel method

Thin films of delafossite of CuAlO2 laminar crystals on metal substrates (Ni plates) were prepared by sol–gel processing and subsequent thermal treatment in vacuum. The influence of annealing treatment on surface morphologies and structure of the samples is discussed. Field-emission scanning electron microscope (FESEM) shows the laminar surface architecture of the as-prepared CuAlO2 thin films. The electrical property of sample was investigated by current–voltage analysis, which indicates that a rectifying junction between CuAlO2 film and metal substrate is formed and forward current exceeds reverse current by a factor of up to three. Otherwise, the photoelectrochemical characteristics recorded under 250 mW/cm2 illumination show that the as-prepared thin film electrode which was annealed at 1150 °C for 4 h in vacuum possesses the highest photocurrent density, which is 0.7 mA/cm2 at 0 V vs Ag/AgCl.