Ulianova V. Acoustic wave sensors based on nanostructured zinc oxide

The dissertation is devoted to the development of physical and technological bases of design and study of the sensitivity of the acoustic wave sensors based on nanostructured zinc oxide. The simulation of the piezoelectric properties of nanostructured ZnO layer was carried out in the multilayered structure and increasing of the energy-conversion efficiency was shown. The sensitivity of the sensors based on BAW and SAW with nanostructured layers, sensitive to the mass and electrical load, were analyzed. It was confirmed a significant improvement in the mass sensor sensitivity of both types of sensors due to the increasing of the sensitive element's surface area. The relationships between the parameters of synthesis and structural properties of nanostructured ZnO and Al-doped ZnO in the shape of nanorods on different substrates were established. The synthesis technology of nanostructured ZnO was improved on the basis of the defined mechanisms. The high-sensitive prototypes of UV radiation sensors based on SAW resonator on the substrate of 128°YX-LiNbO3 with apodized interdigital transducers and reversing multistrip coupler and the sensitive layer based on nanostructured ZnO and ZnO:Al were developed and investigated. The major, as compared with existing sensors, frequency shift of 138±1,9 kHz at a lower radiation power of 46 mW/cm2 with a wavelength of 365±3 nm for the SAW sensor with nanostructured ZnO sensing layer (110±2,1 kHz for ZnO:Al sensing layer) was obtained by the method for measuring of resonator frequency shift. A method of reducing the recovery time of the sensors based on nanostructured ZnO and ZnO:Al up to 45 s after UV exposure by application of the gas discharge plasma on sensor surface was introduced to provide the fast discharge.