Conversion of amorphous TiO2 coatings into their crystalline form using a novel microwave plasma treatment
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|Title:||Conversion of amorphous TiO2 coatings into their crystalline form using a novel microwave plasma treatment||Authors:||Dang, Binh H.Q.
MacElroy, J. M. Don
Dowling, Denis P.
|Permanent link:||http://hdl.handle.net/10197/2896||Date:||25-Jul-2011||Abstract:||Crystalline titanium dioxide (TiO2) coatings have been widely used in photo-electrochemical solar cell applications. In this study, TiO2 and carbon-doped TiO2 coatings were deposited onto unheated titanium and silicon wafer substrates using a DC closed-field magnetron sputtering system. The resultant coatings had an amorphous structure and a post-deposition heat treatment is required to convert this amorphous structure into the photoactive crystalline phase(s) of TiO2. This study investigates the use of a microwave plasma heat treatment as a means of achieving this crystalline conversion. The treatment involved placing the sputtered coatings into a 2.45 GHz microwave-induced nitrogen plasma where they were heated to approximately 550°C. It was observed that for treatment times as short as 1 minute, the 0.25-µm thick coatings were converted into the anatase crystalline phase of TiO2. The coatings were further transformed into the rutile crystalline phase after treatments at higher temperatures. The doping of TiO2 with carbon was found to result in a reduction in this phase transformation temperature, with higher level of doping (up to 5.8% in this study) leading to lower anatase-to-rutile transition temperature. The photoactivity performance of both doped and un-doped coatings heat-treated using both furnace and microwave plasma was compared. The carbon-doped TiO2 exhibited a 29% increase in photocurrent density compared to that observed for the un-doped coating. Comparing carbon-doped coatings heat-treated using the furnace and microwave plasma, it was observed that the latter yielded a 19% increase in photocurrent density. This enhanced performance may be correlated to the differences in the coatings’ surface morphology and band gap energy, both of which influence the coatings’ photoabsorption efficiency.||Funding Details:||Science Foundation Ireland||Type of material:||Journal Article||Publisher:||Elsevier||Copyright (published version):||2010 Published by Elsevier B.V.||Keywords:||Titanium dioxide;Magnetron sputtering;Carbon doping;Microwave plasma;Phase transformation||Subject LCSH:||Titanium dioxide films
Phase transformations (Statistical physics)
|DOI:||10.1016/j.surfcoat.2011.03.075||Language:||en||Status of Item:||Peer reviewed|
|Appears in Collections:||Mechanical & Materials Engineering Research Collection|
Solar Energy Conversion (SEC) Cluster Research Collection
Chemical and Bioprocess Engineering Research Collection
Electrical and Electronic Engineering Research Collection
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