The III-nitride semiconductor n-InxGa1-xN was investigated by optical absorbance and luminescence measurements and by various photoelectrochemical methods. Evidence is found for the presence of localized states and compositional fluctuations. Upon illumination with the appropriate wavelength and positive polarization in an indifferent electrolyte, i.e., aqueous 1 mol L-1 HCl, photocurrent flow is observed, resulting in the photoanodic etching of the solid. Measurements of the quantum efficiency Q and the transient photocurrent show that recombination of photogenerated charge carriers competes effectively with photoanodic dissolution.