| Title: | Enhanced sensing of nonpolar volatile organic compounds by silicon nanowire field effect transistors |
| Author(s): | Paska Y; Stelzner T; Christiansen S; Haick H; |
| Address: | "The Department of Chemical Engineering and Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel" |
| ISSN/ISBN: | 1936-086X (Electronic) 1936-0851 (Linking) |
| Abstract: | "Silicon nanowire field effect transistors (Si NW FETs) are emerging as powerful sensors for direct detection of biological and chemical species. However, the low sensitivity of the Si NW FET sensors toward nonpolar volatile organic compounds (VOCs) is problematic for many applications. In this study, we show that modifying Si NW FETs with a silane monolayer having a low fraction of Si-O-Si bonds between the adjacent molecules greatly enhances the sensitivity toward nonpolar VOCs. This can be explained in terms of an indirect sensor-VOC interaction, whereby the nonpolar VOC molecules induce conformational changes in the organic monolayer, affecting (i) the dielectric constant and/or effective dipole moment of the organic monolayer and/or (ii) the density of charged surface states at the SiO(2)/monolayer interface. In contrast, polar VOCs are sensed directly via VOC-induced changes in the Si NW charge carriers, most probably due to electrostatic interaction between the Si NW and polar VOCs. A semiempirical model for the VOC-induced conductivity changes in the Si NW FETs is presented and discussed" |
| Keywords: | "Electric Conductivity Hydrophobic and Hydrophilic Interactions Nanowires/*chemistry Silanes/chemistry Silicon/*chemistry *Transistors, Electronic Volatile Organic Compounds/*analysis;" |
| Notes: | "MedlinePaska, Yair Stelzner, Thomas Christiansen, Silke Haick, Hossam eng Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. 2011/06/09 ACS Nano. 2011 Jul 26; 5(7):5620-6. doi: 10.1021/nn201184c. Epub 2011 Jun 7" |
