Subbandgap Photocurrent of a Ru‐Covered n‐GaAs|Acidic‐Electrolyte Junction

Abstract The subbandgap photocurrent dependence on electrode potential and light energy has been investigated for the n‐GaAs(100) | 1 M HCl junction after surface modification by electroless deposition of ruthenium. A pronounced peak in the photocurrent‐potential curve was found for Ru‐treated electrodes between −0.6 and −0.1 V/SCE. This behaviour is explained in a model simulation for the photocurrent which takes into account the hole generation in a Ru‐induced surface state by absorption of subbandgap light.