Fabrication of a room-temperature H
2
S gas sensor based on SnO
2
nanoporous films by
pulse laser deposition method
Cristian Viespe
Laser Department, National Institute of Laser, Plasma and Radiation Physics, Magurele-
Bucharest, Romania
E-mail:
Hydrogen sulphide is one the most common toxic gases, for this reason is very important
to develop highly sensitive sensors (under ppm) at room temperature, with a very fast response
(of the order of seconds), and low cost. Unfortunately, sensors developed for H
2
S
detection have
some important drawbacks such as
, the poor sensitivity at room operating temperature. Our work
aims to achieve sensors with a high sensitivity, stable and fast response, at concentration lower
than 20 ppm, for detecting H
2
S even at room temperature.
The nanoporous sensitive layer was directly deposited onto a quartz substrate using the
picosecond laser ablation method. The fabricated sensors were ‘delay line’ type (quartz substrate,
70 MHz central frequency). X-ray diffraction (XRD) and scanning electron microscopy (SEM)
were employed to investigate the influence of different experimental conditions, such as laser
power density and inert gas pressure, on the morphological proprieties of SnO
2
thin films. The
sensor performance (sensitivity, detection limit, and response time) at RT, for H
2
S
concentrations in synthetic air between 10 - 20 ppm were studied. We obtained a sensitivity and
detection limit of 10 ppm, for RT operation. The response time was between 15-20 s for H
2
S
concentrations between 10-20 ppm in synthetic air.
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