Kamimura, J.; Bogdanoff, P.; Ramsteiger, M.; Geelhaar, L.; Riechert, H.: Photoelectrochemical properties of InN nanowire photoelectrodes for solar water splitting. Semiconductor Science and Technology 31 (2016), p. 074001/1-6
InN nanowires were grown on Si(111) substrates by plasma-assisted molecular beam epitaxy. Raman spectroscopy showed that the nanowires were strain-free and allowed to deduce a free carrier concentration of 1-2×1018 cm-3. This value was confirmed by a Mott-Schottky analysis of electrolyte-based capacitance-voltage measurements. In addition, these measurements revealed directly the existence of a surface accumulation layer in the InN nanowires. In cyclic voltammetry measurements under irradiation from a Xe lamp with about 100 mW/cm2, high photocurrents of about 4 and 11 mA/cm2 were observed at 1.23 and 1.63 V bias potential vs. reversible hydrogen electrode, respectively, using H2O2 as a hole scavenger. By comparing the photocurrent with and without H2O2, the main limiting factor in the performance of InN nanowire photoanodes was identified to be the poor catalytic efficiency for water oxidation at the surface, followed by parasitic bulk recombination.