Progress in sputtered tungsten trioxide for photoelectrode applications Marsen, Bjorn; Miller, Eric L; Paluselli, Daniela; Rocheleau, Richard E [Hawaii Natural Energy Institute, University of Hawaii at Manoa, Honolulu, HI 96822 (United States)] 14 SOLAR ENERGY; ARGON; TUNGSTEN OXIDES; TUNGSTATES; TUNGSTEN; HYDROGEN; NITROGEN; FILMS; PHOTOVOLTAIC EFFECT; CALCIUM NITRIDES; POLYCRYSTALS; OXYGEN; PHOTOCURRENTS; SILICON; DOPED MATERIALS; PHOTOELECTROCHEMICAL CELLS; ABSORPTION; RED SHIFT; COMPACTS; DEPOSITION; EFFICIENCY; EQUIPMENT; GROWTH; ILLUMINANCE; MORPHOLOGY In the context of photoelectrochemical water-splitting, tungsten oxide films have been fabricated at low processing temperatures (<250{sup o}C) by reactive sputtering from tungsten targets in an argon/oxygen ambient. The films have a dense, compact morphology and show columnar growth. Amorphous and highly polycrystalline films can be produced depending on the deposition conditions; polycrystalline phases appear only at higher temperatures and under certain sputter target conditions. Large crystallites proved beneficial to photoelectrochemical performance. A maximum photocurrent of 2.7mA/cm{sup 2} (at 1.6 V vs SCE) was observed in 0.33MH{sub 3}PO{sub 4} under AM 1.5 Global illumination, exceeding published results for material fabricated at higher temperatures (in the 400-600{sup o}C range). Doping of sputtered tungsten oxide films with nitrogen results in a red-shifted absorption edge, but so far not in increased photocurrents. The maximum photocurrent of a nitrogen-doped sample was measured at 2.3mA/cm{sup 2} (at 1.6 V vs SCE). A multi-junction photoanode based on the best available sputtered WO{sub 3} film and an amorphous silicon photovoltaic device is projected to operate at 2.2% solar-to-hydrogen efficiency. (author) Available from: http://dx.doi.org/10.1016/j.ijhydene.2006.01.022 United Kingdom 2007-10-15 English Journal Article Journal Name: International Journal of Hydrogen Energy; Journal Volume: 32; Journal Issue: 15; Other Information: Elsevier Ltd. All rights reserved Medium: X; Size: page(s) 3110-3115 https://doi.org/10.1016/J.IJHYDENE.2006.01.022 [] 15 32 Journal ID: ISSN 0360-3199; IJHEDX; TRN: GB07V3618 GB 2010-01-01 20969400