Synthesis and photoelectric characterization of delafossite conducting oxides CuAlO_2 laminar crystal thin films via sol-gel method

摘要

Thin films of delafossite of CuAlO_2 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 CuAlO_2 thin films. The electrical property of sample was investigated by current-voltage analysis, which indicates that a rectifying junction between CuAlO_2 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/cm~2 illumination show that the as-prepared thin film electrode which was annealed at 1150℃ for 4 h in vacuum possesses the highest photocurrent density, which is 0.7 mA/cm~2 at 0 V vs Ag/AgCl.