Dresden 2011 – scientific programme
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O: Fachverband Oberflächenphysik
O 60: Poster Session IV (Solid/liquid interfaces; Semiconductors; Oxides and insulators; Graphene; Plasmonics and nanooptics; Electronic Structure; Surface chemical reactions; Heterogeneous catalysis)
O 60.19: Poster
Wednesday, March 16, 2011, 17:30–21:00, P4
III-V semiconductors for photoelectrochemical applications: surface preparation and characterization — •Dominic Fertig, Birgit Schächner, Wofram Calvet, Bernhard Kaiser, and Wolfram Jaegermann — TU Darmstadt, Fachbereich Materialwissenschaft, Fachgebiet Oberflächenforschung
III-V semiconductors are promising reference systems for photoelectrochemical energy conversion. Therefore we have studied the influence of different acids and acidic solutions on the etching of p-doped gallium-arsenide and gallium-phosphide single crystal surfaces. From our experiments we conclude, that etching with HCl and subsequent annealing up to 450∘C gives the best results for the removal of the carbonates and the oxides without affecting the quality of the sample. By treating the surfaces with "piranha"-solution (H2SO4:H2O2:H2O/7:2:1), the creation of an oxide layer with well defined thickness can be achieved. For the creation of an efficient photoelectrochemical cell, Pt nanoparticles have been deposited from solution. These surfaces are then characterized by photoelectron spectroscopy and AFM. Further electrochemical measurements try to correlate the effect of the surface cleaning and the Pt deposition on the photoactivity of the GaAs- and GaP-semiconductors.