Greatly Enhanced Sub‐Bandgap Photocurrent in Porous GaP Photoanodes

It has been found that porous GaP photoanodes show considerable photocurrent when illuminated with sub‐bandgap light, in contrast to flat electrodes. The origin of this enhanced response to sub‐bandgap light was investigated. Due to the morphology of the porous structure, photons are more effectively absorbed. Light absorption by surface electronic levels is found to be an important source of sub‐bandgap photocurrent.