Zarine Simonyan

This study aimed to develop a high-performance liquefied petroleum gas (LPG) sensor based on the Fe2O3:ZnO material. A solid-state synthesis of the ceramic target with Fe2O3 and ZnO nanopowders is presented. LPG sensing nanostructured films were obtained by the high-frequency magnetron sputtering method. The thickness and surface morphology of the sensing layers were determined by thickness measuring profilometer and scanning electron microscope, respectively. The crystallographic properties and elemental mapping analysis of the Fe2O3:ZnO material were investigated by transmission electron microscopy. Energy-dispersive X-ray elementary analysis highlighted the presence of single elements available in the Fe2O3:ZnO material. Further, a chemo-resistive sensor based on a thin film of the Fe2O3:ZnO nanostructure was fabricated onto the Multi-Sensor-Platform, and its gas sensing properties were investigated towards LPG. The sensor with Pd catalytic particles showed the highest gas response at 200°C. The LPG sensing parameters like sensor response and response/recovery times were investigated at different operating temperatures. The minimum response and recovery times of the sensor corresponding to an LPG concentration of 2000 ppm were found to be 26 and 15 s, respectively. The investigated sensing parameters demonstrate that the fabricated LPG sensor based on the Fe2O3:ZnO semiconductor nanostructures is challenging for the detection of low concentrations of LPG at relatively low temperatures.

In this report, a Fe₂O₃:ZnO sputtering target and a nanograins-based sensor were developed for the room temperature (RT) detection of hydrogen peroxide vapor (HPV) using the solid-state reaction method and the radio frequency (RF) magnetron sputtering technique, respectively. The characterization of the synthesized sputtering target and the obtained nanostructured film was carried out by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray (EDX) analyses. The SEM and TEM images of the film revealed its homogeneous granular structure, with a grain size of 10–30 nm and an interplanar spacing of Fe₂O₃ and ZnO, respectively. EDX spectroscopy presented the real concentrations of Zn in the target material and in the film (21.2 wt.% and 19.4 wt.%, respectively), with a uniform distribution of O, Al, Zn, and Fe elements in the e-mapped images of the Fe₂O₃:ZnO film. The gas sensing behavior was investigated in the temperature range of 25–250 °C with regards to the 1.5–56 ppm HPV concentrations, with and without ultraviolet (UV) irradiation. The presence of UV light on the Fe₂O₃:ZnO surface at RT reduced a low detection limit from 3 ppm to 1.5 ppm, which corresponded to a response value of 12, with the sensor’s response and recovery times of 91 s and 482 s, respectively. The obtained promising results are attributed to the improved characteristics of the Fe₂O₃:ZnO composite material, which will enable its use in multifunctional sensor systems and medical diagnostic devices.

In this paper, the ZnO target was synthesized by the solid-state reaction method and a nanostructured thin film was deposited by the RF (radio frequency) magnetron sputtering method on a Multi-Sensor-Platform. The obtained ZnO nanostructured film was investigated as the sensing material. Energy-Dispersive X-ray (EDX) analysis indicated the existence of La in the synthesized ZnO material. Scanning Electron Microscope (SEM) images of the film showed the grain sizes in the range of 20–40 nm. Sensor performance characteristics such as a dynamic response, response and recovery times, and ethanol detection range were investigated at 50–300 °C. A sensitivity was observed at extremely low concentrations of ethanol (0.7 ppm). The minimum response and recovery times of the sensor corresponding to 675 ppm ethanol vapor concentration at 250 °C were found to be 14 s and 61 s, respectively. The sensor showed a high response, good selectivity, fast response/recovery behavior, excellent repeatability toward ethanol vapor, and low sensitivity toward humidity. These characteristics enable the use of a ZnO based sensor for ethanol detecting applications.