Enhanced Piezoelectric Output and Electromechanical Response of ZnO Film Sensors via Orientation Induction and Rapid Deposition Strategies

Zinc oxide (ZnO) films, as representative piezoelectric semiconductors, have garnered considerable interest in ultrasonic testing. Current research challenges include maintaining the consistency of continuous c-axis orientation and determining the fundamental link between the electrical structure and piezoelectric response. Accordingly, we have proposed ZnO films incorporated with an orientation-inducing layer (OIL), utilizing orientation induction and rapid deposition technology to regulate the growth structure of the ZnO films. Furthermore, the influence of the competitive mechanism between the film growth and lateral diffusion on the film’s growth structure has been investigated. Piezoelectric force microscopy (PFM) analysis demonstrated the regulation and enhancement of ZnO piezoelectric polarization by the OIL. The enhancement mechanism of OIL on film performance was revealed via experimental examination of the film structure, morphology, crystallization orientation, oxygen vacancies, carrier concentration, band structure, and density of states based on density functional theory (DFT). Benefiting from the superior electromechanical response of the ZnO OIL sensor, characterized by fast response recovery times of 2.4 ms/7.7 ms and a sensitivity of 1.09 V/N, the device has successfully demonstrated practical applications in both motion pressure detection and bolt axial force measurement. These findings provide new insights into the ultrasonic detection for aerospace applications of ZnO OIL piezoelectric devices and demonstrate significant potential for health monitoring in connection systems.