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Investigation of the UV/O 3 treatment of ultrananocrystalline diamond films
Author(s) -
Kulisch W.,
Popov C.,
Gilliland D.,
Ceccone G.,
Rossi F.,
Reithmaier J. P.
Publication year - 2010
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.3264
Subject(s) - diamond , materials science , nanotechnology , chemical engineering , composite material , engineering
Abstract Surface analytical techniques such as XPS, time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) and contact angle measurements have been applied to investigate the effects of UV/O 3 treatments used to render the original hydrogen termination of ultrananocrystalline diamond/amorphous carbon composite films to an OH‐termination. The main parameter varied was the treatment time. For comparison purposes, a sample treated by a microwave O 2 plasma for 10 min, and a sample treated with UV light without the ozone‐forming 185 nm emission have also been investigated. The standard UV/O 3 treatment leads to the following effects: i) the surface becomes oxidized with a final oxygen surface concentration of about 10%; ii) this oxygen is present at the surface mainly in the form of OH groups; iii) the contact angle against purified water drops from 85° for as‐grown samples to 5° ± 2° for UV/O 3 ‐treated surfaces; iv) the surface energy increases by a factor of two, reaching 78 mN/m; in addition, this surface energy is almost exclusively of polar nature. These developments are almost completed after 20 min of UV/O 3 treatment. Similar results can be achieved by O 2 plasma treatment, while blocking the ozone‐forming 185 nm line of the UV lamp leads to only marginal changes of the as‐grown surface, thus proving that O 3 plays a crucial role in the oxidation process. Copyright © 2010 John Wiley & Sons, Ltd.