Title

Controlling the Sensing Properties of Silicon Nanowires via the Bonds Nearest to the Silicon Nanowire Surface

Abstract

ABSTRACT: Controlling the sensing properties of a silicon nanowire field effect transistor is dependent on the surface chemistry of the silicon nanowire. A standard silicon nanowire has a passive oxide layer (native oxide), which has trap states that cause sensing inaccuracies and desensitize the surface to nonpolar molecules. In this paper, we successfully modified the silicon nanowire surface with different nonoxide C3 alkyl groups, specifically, propyl (Si−CH2−CH2−CH3), propenyl (Si−CHCH−CH3), and propynyl (Si−CC−CH3) modifications. The effect of the near surface bond on the sensor sensitivity and stability was explored by comparing three C3 surface modifications. A reduction of trap-states led to greater sensor stability and accuracy. The propenyl-modified sensor was consistently the most stable and sensitive sensor, among the applied sensors. The propenyl- and propynylmodified sensors consistently performed with the best accuracy in identifying specific analytes with similar polarity or similar molecular weights. A combination of features from different sensing surfaces led to the best rubric for specific analytes identification. These results indicate that nonoxide sensor surfaces are useful in identifying specific analytes and that a combination of sensors with different surfaces in a cross-reactive array can lead to specific analytes detection.

Publication Date

6-3-2015

Journal Title

ACS Applied Materials & Interfaces

Publisher

American Chemical Society

Digital Object Identifier (DOI)

10.1021/acsami.5b01721

Document Type

Article