Structure of n-Alkyltrichlorosilane Monolayers on Si(100)/SiO2

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• 作者：H.-G. Steinr眉ck ; J. Will ; A. Magerl ; B. M. Ocko
• 刊名：Langmuir
• 出版年：2015
• 出版时间：November 3, 2015
• 年：2015
• 卷：31
• 期：43
• 页码：11774-11780
• 全文大小：452K
• ISSN：1520-5827

文摘

The structure of n-alkyltrichlorosilane self-assembled monolayers (SAMs) of alkyl chain lengths n = 12, 14, 18, and 22 formed on the amorphous native oxide of silicon (100) has been investigated via angstrom-resolution surface X-ray scattering techniques, with particular focus on the proliferation of lateral order along the molecules鈥?long axis. Grazing incidence diffraction shows that the monolayer is composed of hexagonally packed crystalline-like domains for n = 14, 18, and 22 with a lateral size of about 60 脜. However, Bragg rod analysis shows that 鈭?2 of the CH₂ units are not included in the crystalline-like domains. We assign this, and the limited lateral crystallites鈥?size, to strain induced by the size mismatch between the optimal chain鈥揷hain and headgroup鈥揾eadgroup spacings. Analysis of X-ray reflectivity profiles for n = 12, 14, and 22 shows that the density profile used to successfully model n = 18 provides an excellent fit where the analysis-derived parameters provide complementary structural information to the grazing incidence results.