Investigation and development of highly sensitive gas sensors based on metal oxide semiconductors for air quality monitoring.

The project aim
The project goal is the development of highly sensitive miniaturized gas sensors based on
a polycrystalline MOS and to enhance their morphological, electrical and optical properties, as
well as to increase the sensitivity and response time to toxic gases.

The main tasks of the project
In order to achieve the goal, the next research tasks are listed below:
1) Fabrication of nano films for MOS based gas sensors. MOS nano films will be synthesized on
a glass substrate using magnetron sputtering. Alternatively, nanofibers will be synthesized using
electrospinning technique. Magnetron sputtering and electrospinning are a unique techniques
which offers a simple and easy method of large-scale nanostructure preparation;
2) Modification by doping with transition metals and beam treatment. The first, we will modified
IDT (interdigital transducer) electrodes using physical vapor deposition of gold particles on the
surface of a specialized substrate. Then, MOS based nano films with IDT electrodes will be
doped with titanium (or other transition mental). In addition, obtained nano films will be
irradiated using DC-60 to improve the gas sensing properties;
3) Physical-chemical and electrical characterization of synthesized nano films. The following
advanced methods of the thin-film characterization will be conducted: AFM, XRD, SEM, XPS,
ellipsometry and EDAX. To improve the electrical properties of the sensor, the morphology and
structures of the novel MOS gas sensors will be optimized. These properties of the sensors will
be controlled by varying the type and amount of the dopant;
4) Measurement of gas sensitivity, stability and selectivity. Measurements of gas sensitivity will
be carried out under the temperatures from 300 K to 725 K and at various concentrations of
gases (from 10 ppb to 500 ppm). The optimal operating temperature for the synthesized gas
sensor will be determined. The sensitivity, selectivity and stability of sensor will be calculated
for the further improvement of these parameters;
5) Development and assembly of a miniature gas sensor and investigation on gas emissions. The
miniaturized gas sensor will be designed and investigated for gas emission. The prototype of gas
sensor will be assembled by Arduino platform and tested under various gas concentrations with
different temperature conditions (from room temperature to 725 K).

Abstract
Due to the increase in atmospheric pollution, including various toxic gases, the effective
detection of pollutants has become a crucial objective over the last years. Harmful and toxic
gases are usually detected by gas sensors based on optical, acoustic, and metal oxide
semiconductor (MOS) sensors. Among them, MOS sensors are in high demand for industrial
sectors due to their low cost, wide temperature range operation capability, as well as effectivity
in the detection of a variety of toxic gases. Furthermore, toxic gases are also a serious safety
issue for energy storage systems. Achieving a high level of safety and reliability is especially
important for lithium-ion batteries (LIB), which release various toxic substances during thermal
dispersal resulting in a fire. Thus, this research targets the synthesize of a novel highly sensitive
gas sensors based on MOS (ZnO, SnO 2 and WO 3 ) by the methods of magnetron sputtering and
electrospinning with doping transition metal to determine harmful and toxic gases in low
concentration.