Dresden 2014 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 17: Semiconductor Substrates
O 17.7: Vortrag
Montag, 31. März 2014, 17:30–17:45, PHY C 213
In situ study of water adsorption on InP(100) surfaces — •Matthias M. May1,2, Hans-Joachim Lewerenz1,3, and Thomas Hannappel1,4 — 1Helmholtz-Zentrum Berlin, Institute of Solar Fuels — 2Humboldt-Universität zu Berlin, Institut für Physik — 3California Institute of Technology, Pasadena, USA — 4TU Ilmenau, Institut für Physik, Fachgebiet Photovoltaik
Photoelectrochemical water splitting with semiconductors promises to harvest solar energy directly and efficiently in the form of chemical energy. The most critical part of potential devices is the solid-electrolyte interface, which has to enable efficient charge-transfer and simultaneously block corrosion.
III-V semiconductors such as GaP or InP are an interesting light absorber material class, but their surface has to be designed appropriately for solar water splitting applications.[1] We perform water (oxygen) adsorption experiments on atomically well-defined InP(100) surfaces prepared by metal-organic vapour phase epitaxy. Monitoring the adsorbate-induced surface modifications of different surface reconstructions with reflection anisotropy spectroscopy and photoelectron spectroscopy, we aim to develop criteria for the design of III-V electrode surfaces.[2] We find that In-rich, (2 × 4) reconstructed and p(2 × 2)/c(4 × 2) reconstructed, P-rich surfaces exhibit a distinctly different initial interaction with the adsorbates, which could explain why In-rich InP(100) photocathodes perform so well.
Hannappel et al., in Photoelectrochemical Water Splitting, RSC Publishing (2013). [2] May et al., New J. Phys. 15:103003 (2013).