Covalently attached monolayers on crystalline hydrogen-terminated silicon: extremely mild attachment by visible light.
A very mild method was developed for the attachment of high-quality organic monolayers on crystalline silicon surfaces. By using visible light sources, from 447 to 658 nm, a variety of 1-alkenes and 1-alkynes were attached to hydrogen-terminated Si(100) and Si(111) surfaces at room temperature. The presence and the quality of the monolayers were evaluated by static water contact angles, X-ray photoelectron spectroscopy, and IR spectroscopy. Monolayers prepared by thermal, UV light, or visible light initiation were compared. Additionally, the ability of infrared reflection-absorption spectroscopy to study organic monolayers on silicon was explored. A reaction mechanism is discussed on the basis of investigations of the reaction behavior of 1-alkenes with silicon wafers with varying types and levels of doping. Finally, a series of mixed monolayers derived from the mixed solutions of a 1-alkene and an omega-fluoro-1-alkene were investigated to reveal that the composition of the mixed monolayers was directly proportional to the molar ratio of the two compounds in the solutions.
Sun
Qiao-Yu
QY
Laboratory of Organic Chemistry, Wageningen University and Research Center, Dreijenplein 8, 6703 HB Wageningen, The Netherlands.
de Smet
Louis C P M
LC
van Lagen
Barend
B
Giesbers
Marcel
M
Thüne
Peter C
PC
van Engelenburg
Johan
J
de Wolf
Frits A
FA
Zuilhof
Han
H
Sudhölter
Ernst J R
EJ