Assistant Professor, Department of Chemical Engineering, Delft University of Technology, Delft, The Netherlands

Surface Modification Strategies on Silicon Nanowire-based Sensors

High control over the interfacial properties of a sensor surface is important for the functioning of sensor devices. A brief overview of different surface modification strategies on sensor platforms will be given, particularly those applied on silicon nanowire-based sensors. Silicon nanowires are often covered with silicon oxide and hence silanization methods have been used in most cases (Figure 1, top).¹ One problem, however, is that –in terms of silanization-based surface modification– one cannot discriminate between the oxide of the nanowire and the background oxide; both are modified, which results in a reduced sensor sensitivity.

Figure 1. Reaction schemes of the modification of (top) oxide-covered surfaces with silane derivatives and (bottom) H-terminated silicon surfaces with 1-alkenes.

The modification of the background oxide can be overcome by stripping of the oxide on the nanowires via etching. This is possible via time-controlled etching as the oxide on the nanowire is typically <10 nm in thickness, while the background oxide is thicker. The resulting H-terminated nanowire can now selectively be modified using a hydrosilylation reaction scheme (Figure 1, bottom).²

This presentation will address the question of whether or not this is the way to go.

 

¹Organic Surface Modification of Silicon Nanowire-Based Sensor Devices, de Smet L.C.P.M.; Ullien, D.; Mescher, M.; Sudhölter, E.J.R. in: Nanowires / Book 2 - ISBN 978-953-307- 563-1, Publisher: InTech, Editor: Dr Abbass Hashim (expected: June 2011)
²Bunimovich, Y.L.; Shin, Y.S.; Yeo, W.S.; Amori, M.; Kwong, G.; Heath, J.R. J. Am. Chem. Soc. 2006, 128, 16323-16331.
 

---

About the Speaker:

Louis de Smet received the M.Sc. degree in Molecular Sciences and the Ph.D. degree in the field of organic monolayers from Wageningen University, Wageningen, The Netherlands, in 2001 and 2006, respectively.

He then worked as a Postdoctoral Researcher on plasma polymers with Ian Wark Research Institute at the University of South Australia. Mid 2007, he was appointed as an Assistant Professor with the Department of Chemical Engineering, Delft University of Technology, Delft, The Netherlands. His research interests include the preparation and characterization of functional organic monolayers and polymer films and their application to the surface of different sensor platforms, including nanowire-based sensors and interdigitated electrodes.

He is the recipient of the Talent Stipend (2006) and the Veni Grant (Innovational Research Incentives Scheme, 2007) from the Netherlands Organization for Scientific Research (NWO).