The Photoresponse of Iron- and Carbon-Doped TiO2 (Anatase) Photoelectrodes

• Published in: Journal of electroceramics 2004-07, Vol.13 (1-3), p.177-182
• Main Authors: Enache, Cristina S., Schoonman, Joop, Krol, Roel Van
• Format: Article
• Language: English
• ISSN: 1385-3449; 1573-8663
• DOI: 10.1007/s10832-004-5095-x

Fe-doped and C-doped anatase TiO^sub 2^ films were made by spray pyrolysis. For Fe:TiO^sub 2^, a small sub-bandgap photoresponse is observed which is attributed to the presence of additional states located just above the valence band. Although no visible-light photoresponse is observed for carbon-doped TiO^sub 2^ due to the low carbon content, the photocurrent at hν > E^sub g^ is significantly larger than for undoped TiO^sub 2^. At the same time, the donor density of oxidized C-doped TiO^sub 2^ is > 1.9× 10^sup 19^ cm^sup -3^, compared to 3.2× 10^sup 17^ cm^sup -3^ for undoped TiO^sub 2^. Assuming that only light absorbed in the depletion layer contributes to the photocurrent, the photoresponse of C-doped anatase (at 330 nm) is 16 times larger than that predicted for undoped TiO^sub 2^ under similar conditions. The strong enhancement of the absorption is most likely caused by a change in the electronic structure of the material due to the presence of carbon and/or related defects. Photoluminescence measurements suggest that the defects present in oxidized carbon-doped anatase resemble those present in undoped, reduced TiO^sub 2^.[PUBLICATION ABSTRACT]