Self-assembled silane monolayers: fabrication with nanoscale uniformity.
Illustrating direct connections between surface chemical events and mechanical and topological characteristics of self-assembled monolayers derived from octadecyltrichlorosilane (OTS) adsorption on Si(100), layers prepared in the presence and absence of moisture have been characterized. Uniform and robust self-assembled monolayers are demonstrated provided the Si(100) surface is fully hydroxylated by treatment in piranha solution and the dried surface is exposed to OTS under strict anhydrous conditions. With nanoscale resolution, the uniform mechanical properties are confirmed by interfacial force microscopy while the uniform topological properties are evident in atomic force microscopy images. The monolayer character of the OTS coverage is confirmed by X-ray photoelectron spectroscopy, ellipsometry, and patterning experiments. Analogous surfaces, prepared in the presence of moisture, exhibit nonuniform topological and mechanical properties.
Wang
Mingji
M
Center for Mechanics of Solids, Structures and Materials, Department of Aerospace Engineering and Engineering Mechanics, University of Texas at Austin, Austin, Texas 78712, USA.
Liechti
Kenneth M
KM
Wang
Qi
Q
White
J M
JM