Enhanced photoelectrochemical water splitting by self-organized metal nanopillars in an oxide semiconductor

Abstract

We demonstrated the spontaneous formation of Ir metal nanopillars embedded in Ir:SrTiO₃ thin films in order to enhance the efficiency of photoelectrochemical water splitting. The interface between the metallic Ir nanopillar and the Ir:SrTiO₃ thin film forms a tubular Schottky junction around each pillar. The photocarrier transport efficiency is strongly enhanced in the depleted interface regions, achieving over 80% utilization of photogenerated carriers under visible light in the 400 to 600 nm wavelength range. The three-dimensional interface concept using spontaneously formed nanopillars would provide us a variety of novel functionalities in oxide and semiconductor devices.