A coplanar electrode operating mode for piezoelectric energy harvesting and self-powered sensing

Piezoelectric semiconductors have emerged as a prominent area of research in recent years due to their unique combination of piezoelectric and semiconductor properties. In this Letter, we propose a piezoelectric device structure featuring coplanar electrodes positioned above the piezoelectric layer. We have conducted a detailed theoretical analysis of the piezoelectric properties of this piezoelectric device. By utilizing a coplanar electrode piezoelectric mode, pressure applied to one electrode generates a potential difference between the two electrodes. Notably, the piezoelectric performance of the device can be adjusted by modifying its structure. Numerical simulations and experimental results indicate that the piezoelectric performance reaches an optimal value when the distance between the electrodes is equal to one-half of the electrode length. Additionally, we have developed a method to enhance the piezoelectric voltage output capability of the device under low load resistance conditions. Specifically, by introducing charge carriers into the piezoelectric layer from the doped silicon substrate, the device's resistance is reduced due to the Schottky contact. The piezoelectric operating mode proposed in this paper facilitates energy harvesting and self-powered sensing, distinguishing it from the d31 and d33 operational modes associated with traditional sandwich device structures, thereby allowing for more versatile device configurations.