Interactive Effect of
Hysteresis and Surface Chemistry
on Gated Silicon Nanowire Gas Sensors
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Abstract
Gated silicon nanowire gas sensors have emerged as promising
devices
for chemical and biological sensing applications. Nevertheless, the
performance of these devices is usually accompanied by a “hysteresis”
phenomenon that limits their performance under real-world conditions.
In this paper, we use a series of systematically changed trichlorosilane-based
organic monolayers to study the interactive effect of hysteresis and
surface chemistry on gated silicon nanowire gas sensors. The results
show that the density of the exposed or unpassivated Si–OH
groups (trap states) on the silicon nanowire surface play by far a
crucial effect on the hysteresis characteristics of the gated silicon
nanowire sensors, relative to the effect of hydrophobicity or molecular
density of the organic monolayer. Based on these findings, we provide
a tentative model-based understanding of (i) the relation between
the adsorbed organic molecules, the hysteresis, and the related fundamental
parameters of gated silicon nanowire characteristics and of (ii) the
relation between the hysteresis drift and possible screening effect
on gated silicon nanowire gas sensors upon exposure to different analytes
at real-world conditions. The findings reported in this paper could
be considered as a launching pad for extending the use of the gated
silicon nanowire gas sensors for discriminations between polar and
nonpolar analytes in complex, real-world gas mixtures