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ACS Appl Mater Interfaces

Title:		Effect of chain length on the sensing of volatile organic compounds by means of silicon nanowires
Author(s):		Wang B; Haick H;
Address:		"The Department of Chemical Engineering and Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel"
Journal Title:		ACS Appl Mater Interfaces
Year:		2013
Volume:		20130613
Issue:		12
Page Number:		5748 - 5756
DOI:		10.1021/am401265z
ISSN/ISBN:		1944-8252 (Electronic) 1944-8244 (Linking)
Abstract:		"Molecularly modified silicon nanowire field effect transistors (SiNW FETs) are starting to appear as promising devices for sensing various volatile organic compounds (VOCs). Understanding the connection between the molecular layer structure attached to the SiNWs and VOCs is essential for the design of high performance sensors. Here, we explore the chain length influence of molecular layers on the sensing performance to polar and nonpolar VOCs. SiNW FETs were functionalized with molecular layers that have similar end (methyl) group and amide bridge bond, but differ in their alkyl chain lengths. The resulting devices were then exposed to polar and nonpolar VOCs in various concentrations. Our results showed that the sensing response to changing the threshold voltage (DeltaVth) and changing the relative hole mobility (Deltamuh/muh-a) have a proportional relationship to the VOC concentration. On exposure to a specific VOC concentration, DeltaVth response increased with the chain length of the molecular modification. In contrast, Deltamuh/muh-a did not exhibit any obvious reliance on the chain length of the molecular layer. Analysis of the responses with an electrostatic-based model suggests that the sensor response in DeltaVth is dependent on the VOC concentration, VOC vapor pressure, VOC-molecular layer binding energy, and VOC adsorption-induced dipole moment changes of molecular layer"
Keywords:		Environmental Monitoring Nanowires/*chemistry Particle Size Silicon/*chemistry Surface Properties Volatile Organic Compounds/*analysis/chemistry;
Notes:		"MedlineWang, Bin Haick, Hossam eng Research Support, Non-U.S. Gov't 2013/06/04 ACS Appl Mater Interfaces. 2013 Jun 26; 5(12):5748-56. doi: 10.1021/am401265z. Epub 2013 Jun 13"