Nanophotonic and plasmonic for chemical sensing
C. Baratto
SENSOR CNR – INO & University of Brescia, Via Branze 45, 25133 Brescia, Italy
E-mail
Metal oxides are well known materials in the field of resistive gas sensors; they can be
prepared as single crystalline nanowires to exploit higher stability and improved optical
properties.
ZnO turns out to be an attractive candidate for blue and UV optoelectronics; nanowires are
applied as optical and electrical gas sensors, single-wire transistors, and UV LED (in
heterojunction with p-type material). SnO
2
nanowires are successfully employed for gas
sensing.
We investigated the photoluminescence (PL), electrical and gas sensing properties of
individual nanowire to better understand the properties of the material as function of the NW
diameter and
optical whispering gallery mode (WGM) resonances excited in zinc oxide
micro- and nanowire cavities.
By using localized surface plasmons to generate hot carriers in noble metal nanostructures
supported on metal oxide nanowires, visible light can produce - in addition to plasmonic
heating - energetic hot electrons (or holes) which may drive chemical reactions on the
supporting semiconductor. Here we will discuss how hot electrons could boost metal oxide
nanowires based chemical gas sensing.
Magneto – optical gas sensing tests have been proved, for the first time, on a system based on
Cobalt and ZnO nanorods. The gas sensing process involves mainly the surface of the ZnO
through a physisorption mechanism, while the Co layer acts only as a magnetic transducer.
We developed innovative applications of metal oxide nanowires to gas sensing at room
temperature based on the above mentioned principles.
The research leading to these results has received funding from NATO project SPS 985043
and from
the European Communities 7th Framework Programme under grant
agreement NMP3-LA-2010-246334.
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