Credit: Image courtesy of Joint Center for Artificial Photosynthesis
Gallium arsenide nanowire arrays grown on a silicon substrate are studied using photoelectrochemistry. The middle photograph shows a scanning electron micrograph of a vertically aligned nanowire array; the figure on right is the band energy diagram of the rectifying nanowire/liquid junction; the figure on the left illustrates oxidative redox reactions of ferrocene to ferrocenium molecules at nanowire surfaces.