Formation of Dense Self-assembled Monolayers of (n-Decyl)trichlorosilanes on Ta/Ta2O5
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- 作者：Randy De Palma ; Wim Laureyn ; Filip Frederix ; Kristien Bonroy ; Jean-Jaques Pireaux ; Gustaaf Borghs ; Guido Maes
- 刊名：Langmuir
- 出版年：2007
- 出版时间：January 16, 2007
- 年：2007
- 卷：23
- 期：2
- 页码：443 - 451
- 全文大小：386K
- 年卷期：v.23,no.2(January 16, 2007)
- ISSN：1520-5827
文摘
Tantalum pentoxide (Ta2O5) is a promising material for the realization of biological interfaces because of its highdielectric constant, its high chemical stability, and its excellent passivating properties. Nevertheless, the depositionof highly organized silane SAMs to realize well-defined and tailored Ta2O5-based (bio)interfaces, has not been studiedin great detail as of yet. In this work, we have investigated the formation of a highly ordered, dense monolayer oftrichlorosilanes on Ta2O5 surfaces. Specifically, two different cleaning procedures for Ta2O5 were compared and(n-decyl)trichlorosilane (DTS) was used to study the effect of both cleaning methods on the silanization of Ta2O5.Both types of cleaning allowed the formation of complete and crystalline DTS monolayers on Ta2O5, in contrast withthe incomplete, disordered silane layer assembled on uncleaned Ta2O5. The deposited self-assembled monolayers werestudied by means of contact angle goniometry, Brewster angle FTIR, X-ray photoelectron spectroscopy, cyclicvoltammetry, and ellipsometry. Infrared analysis exhibited a highly ordered DTS silane film on Ta2O5 and indicateda larger tilt angle of the alkyl chains on this substrate by comparison to DTS on SiO2. Furthermore, with use ofellipsometry and XPS, the silane film thickness on Ta2O5 was determined to be substantially smaller than that reportedin the literature for DTS on SiO2, supporting the observations of an increased tilt angle (~45
) on Ta2O5 than on SiO2(~10). By means of cyclic voltammetry, the formation of a dense, essentially pinhole-free, silane film was observedon the cleaned samples. In conclusion, the fully characterized and optimized procedure for the silanization of Ta2O5surfaces with trichlorosilanes will allow the formation of well-defined, reproducible, and controllable chemical interfaceson Ta2O5.
) on Ta2O5 than on SiO2(~10). By means of cyclic voltammetry, the formation of a dense, essentially pinhole-free, silane film was observedon the cleaned samples. In conclusion, the fully characterized and optimized procedure for the silanization of Ta2O5surfaces with trichlorosilanes will allow the formation of well-defined, reproducible, and controllable chemical interfaceson Ta2O5.