Rational Design of Sub-Parts per Million Specific
Gas Sensors Array Based on Metal Nanoparticles Decorated Nanowire
Enhancement-Mode Transistors
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Abstract
“One key to one lock”
hybrid sensor configuration
is rationally designed and demonstrated as a direct effective route
for the target-gas-specific, highly sensitive, and promptly responsive
chemical gas sensing for room temperature operation in a complex ambient
background. The design concept is based on three criteria: (i) quasi-one-dimensional
metal oxide nanostructures as the sensing platform which exhibits
good electron mobility and chemical and thermal stability; (ii) deep
enhancement-mode field-effect transistors (E-mode FETs) with appropriate
threshold voltages to suppress the nonspecific sensitivity to all
gases (decouple the selectivity and sensitivity away from nanowires);
(iii) metal nanoparticle decoration onto the nanostructure surface
to introduce the gas specific selectivity and sensitivity to the sensing
platform. In this work, using Mg-doped In<sub>2</sub>O<sub>3</sub> nanowire E-mode FET sensor arrays decorated with various discrete
metal nanoparticles (i.e., Au, Ag, and Pt) as illustrative prototypes
here further confirms the feasibility of this design. Particularly,
the Au decorated sensor arrays exhibit more than 3 orders of magnitude
response to the exposure of 100 ppm CO among a mixture of gases at
room temperature. The corresponding response time and detection limit
are as low as ∼4 s and ∼500 ppb, respectively. All of
these could have important implications for this “one key to
one lock” hybrid sensor configuration which potentially open
up a rational avenue to the design of advanced-generation chemical
sensors with unprecedented selectivity and sensitivity