Modeling the
Conduction Mechanism in Chemoresistive
Gas Sensor Based on Single-Crystalline Sn3O4 Nanobelts: A Phenomenological In Operando Investigation
posted on 2024-01-05, 06:04authored byPedro H. Suman, Benjamin Junker, Udo Weimar, Marcelo O. Orlandi, Nicolae Barsan
Investigating
the sensing mechanisms in semiconducting
metal oxide
(SMOx) gas sensors is essential for optimizing their performance across
a wide range of potential applications. Despite significant progress
in the field, there are still many gaps in comprehending the phenomenological
processes occurring in one-dimensional (1D) nanostructures. This article
presents the first insights into the conduction mechanism of chemoresistive
gas sensors based on single-crystalline Sn3O4 nanobelts using the operando Kelvin Probe technique. From this approach,
direct current (DC) electrical resistance and work function changes
were simultaneously measured in different working conditions, and
a correlation between the conductance and the surface band bending
was established. Appropriate modeling was proposed, and the results
revealed that the conduction mechanism in the single-crystalline one-dimensional
nanostructures closely aligns with the behavior observed in single-crystalline
epitaxial layers rather than in polycrystalline grains. Based on this
assumption, relevant parameters were further estimated, including
Debye length, concentration of free charge carriers, effective density
of states in the conduction band, and position of the Fermi level.
Overall, this study provides an effective contribution to understanding
the role of surface chemistry in the transduction of the electrical
signal generated from gas adsorption in single-crystalline one-dimensional
nanostructures.