Please use this identifier to cite or link to this item: http://hdl.handle.net/2445/108189
Title: Charge Transfer Characteristics of n-type In0.1Ga0.9N Photoanode across Semiconductor-Liquid Interface
Author: Caccamo, Lorenzo
Fábrega, Cristian
Marschewski, Marcel
Fündling, Sönke
Gad, A.
Casals Guillén, Olga
Lilienkamp, G.
Hofft, Oliver
Prades García, Juan Daniel
Daum, W.
Waag, Andreas
Keywords: Detectors de gasos
Semiconductors
Transferència de càrrega
Gas detectors
Semiconductors
Charge transfer
Issue Date: 29-Dec-2016
Publisher: American Chemical Society
Abstract: Understanding the mechanisms of charge transfer across the semiconductor/liquid interface is crucial to realize efficient photoelectrochemical devices. Here, the interfacial charge transfer characteristics of n-type In0.1Ga0.9N photoanodes are investigated and correlated to their photo-activity properties measured in phosphate buffered saline solution (pH 7) under illumination conditions. Cyclic voltammetry measurements show evident photoactivity changes as the number of cycles increases. In particular, the photocurrent density reaches its maximum value after 49 voltammetric cycles; meanwhile, the photocurrent onset potential shifts toward more negative cathodic potentials. Electrochemical impedance measurements reveal that, first, the hole transfer process occurs mainly via localized states at the surface and the photocurrent onset potential is dependent on the energetic position of those states. Therefore, the observed initial photocurrent increase and cathodic shift of the photocurrent onset potential can be attributed to a decrease of the transfer resistance and partial passivation of the states at the surface. On the other hand, a gradual oxidation and corrosion of the InGaN surface arises, causing a consequential decrease of the photocurrent. At this point, the charge transfer process occurs predominantly from the valence band. This work provides a basic understanding of the charge transfer mechanisms across the InGaN/liquid interface which can be used to improve the overall photoanode efficiency.
Note: Versió postprint del document publicat a: https://doi.org/10.1021/acs.jpcc.6b09256
It is part of: Journal of Physical Chemistry C, 2016, vol. 120, num. 51, p. 28917-28923
Related resource: https://doi.org/10.1021/acs.jpcc.6b09256
URI: http://hdl.handle.net/2445/108189
ISSN: 1932-7447
Appears in Collections:Articles publicats en revistes (Electrònica)

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