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Controlled Thermal Annealing Tunes the Photoelectrochemical Properties of Nanochanneled Tin‐Oxide Structures
Author(s) -
PalaciosPadrós Anna,
Altomare Marco,
Lee Kiyoung,
DíezPérez Ismael,
Sanz Fausto,
Schmuki Patrik
Publication year - 2014
Publication title -
chemelectrochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 59
ISSN - 2196-0216
DOI - 10.1002/celc.201402002
Subject(s) - crystallinity , annealing (glass) , tin , materials science , tin oxide , photocurrent , band gap , oxide , chemical engineering , analytical chemistry (journal) , metallurgy , optoelectronics , composite material , chemistry , chromatography , engineering
We study the effect of thermal annealing conditions (up to 400 °C) and atmospheres (air, Arand O 2 ) on a newly developed nanochannel tin‐oxide structure. The nanochanneled structures were prepared by self‐organized anodization of metallic tin. Thermal annealing conditions have a strong impact on the crystallinity and content of Sn 2+ defects present in the structure, and thus have a strong influence on the photoresponse characteristics of the films. Photocurrent measurements show that films annealed at 200 °C in Ar atmosphere exhibit a band gap as low as 2.4 eV and a photoresponse in the visible range. This effect is ascribed to a large content of Sn 2+ defects in the structure and the improved crystallinity of the films annealed at this temperature. On the contrary, the Sn 2+ content is decreased when annealing at 400 °C under aerobic conditions, which correlates with a shift in the film band gap to 3.2 eV, closer to the reported value for pure SnO 2 (3.6 eV).