An x‐ray photoemission spectroscopy study of the role of sample preparation on band bending at the interface of Al with poly(p‐phenylene vinylene)

Autor:	K. T. Park, Yongli Gao, E. Ettedgui, Bing R. Hsieh, H. Razafitrimo
Rok vydání:	1994
Předmět:	chemistry.chemical_compound Materials science Band bending X-ray photoelectron spectroscopy chemistry Photoemission spectroscopy Schottky barrier Analytical chemistry General Physics and Astronomy Poly(p-phenylene vinylene) Electronic band structure Surface energy Overlayer
Zdroj:	Journal of Applied Physics. 75:7526-7530
ISSN:	1089-7550 0021-8979
DOI:	10.1063/1.356626
Popis:	We report on our recent x‐ray photoemission spectroscopy investigations of the interface formation of Al with poly(p‐phenylene vinylene) (PPV) prepared under various conditions. We have found that during deposition Al reacts with residual hydroxyl groups in the polymer. In addition, we have found that Schottky barrier formation and the associated band bending depend strongly on surface preparation. Samples converted in situ, containing 5% surface oxygen, show band bending that depends on the thickness of the Al overlayer, with effects arising after as little as 1 A Al. By contrast, a sample converted ex situ, with 10% surface oxygen, is insensitive to aluminum deposition. In view of the results obtained, we feel that surface impurities and adsorbed species may delay Schottky barrier formation by acting as a buffer layer which prevents the PPV substrate from interacting with the growing layer of Al. In the in situ samples where band bending occurs, we find that it takes place after the formation of metallic Al.
Databáze:	OpenAIRE
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