Interface engineering of titanium oxide protected a-Si:H/a-Si:H photoelectrodes for light induced water splitting

• Published in: Applied surface science Vol. 389; pp. 73 - 79
• Main Authors: Ziegler, Jürgen, Yang, Florent, Wagner, Stephan, Kaiser, Bernhard, Jaegermann, Wolfram, Urbain, Félix, Becker, Jan-Philipp, Smirnov, Vladimir, Finger, Friedhelm
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.12.2016
• Subjects: Amorphous silicon solar cell; Band alignment; Photoelectrochemical cell; Photoelectron spectroscopy; Photoelectrochemical cell; Band alignment; Amorphous silicon solar cell; Photoelectron spectroscopy
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2016.07.074

•A two step deposition of a TiO2 protection layer for solar water splitting is investigated.•A reduced amount of oxygen successfully prevents the oxidation of the cell.•Applying the first layer without oxygen leads to a pinned contact.•An Ohmic contact to amorphous Si can be achieved by decreasing the amount of TiOx. TiO2 is a common protection layer on semiconductor electrodes for photoelectrochemical water splitting. We investigate the interface formation of TiO2 on amorphous silicon tandem solar cells by X-ray photoelectron spectroscopy. In order to optimize the contact properties, we prepare TiOx interface layers with various oxygen content by reactive magnetron sputter deposition. We observe, that a TiOx interface layer can reduce the silicon oxide growth during the film deposition on the amorphous silicon, but it forms a non-ohmic contact. The electrochemical investigation shows, that the benefit due to the reduction of the silicon oxide is counteracted by the unfavorable contact formation of TiOx interface layers prepared with low oxygen content.