Dresden 2014 – scientific programme

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O: Fachverband Oberflächenphysik

O 96: Atomic Layer Deposition (DS jpointly with O)

O 96.5: Talk

Friday, April 4, 2014, 10:45–11:00, CHE 91

Control of thickness of SiO2 interfacial layer for photocatalytic water splitting on Si photocathodes — •Chittaranjan Das, Massimo Tallarida, and Dieter Schmeisser — Applied physics and sensors,BTU Cottbus, Germany

Silicon with a band gap of 1.1eV is an excellent candidate for visible photocatalytic water splitting. But p-type Si has a low quantum yield and are less efficient for water splitting [1]. It has been shown that preventing oxidation of Si surface can shift the onset potential for water reduction by about 300mV towards more positive [2]. We investigated in detail the influence of the SiO2 layer thickness on the onset potential for water splitting on Si photocathodes: we used p-type Si substrates covered with SiO2 layers of varying thickness. Then, we deposited a thin TiO2 film on using atomic layer deposition (ALD) to inhibit Si oxidation during the electrochemical experiment. In this way we could shift the onset potential up to 200mV, depending on the SiO2 thickness.

[1]E. L. Warren, S. W. Boettcher, M. G. Walter, H. A. Atwater, and N. S. Lewis: J. Phys. Chem. C 115 (2011) 594. [2]B. Seger, Anders B. Laursen, P. C. K. Vesborg, T. Pedersen, O. Hansen, S. Dahl, I. Chorkendorff, Angew. Chem. Int. Ed. 2012, 51, 9128 *9131