Thickness‐Driven Aluminum Nitride‐Based Piezotronic Device for Concurrent Energy Harvesting and Sensing

ABSTRACT Piezotronic devices have emerged as a potential candidate that offers promising platforms for sustainable energy harvesting and self‐powered devices. Such devices employ strain‐induced piezoelectric polarisation charges as a gate voltage to tune the charge carrier transport at the interface. Leveraging this mechanism, an aluminum nitride (AlN)‐based piezotronic devices are fabricated on silicon substrate using the direct current (DC) sputtering technique. Herein, AlN film thickness is utilised as a key factor to modulate the output voltage and electronic characteristics. An increase in film thickness from 0.8 to 1.6 µm results in an enhancement in crystallite size from 19.35 to ∼23 nm, c‐axis orientation, and columnar growth. The fabricated piezoelectric nanogenerators (PENGs) demonstrate noticeable improvement, achieving a maximum voltage of ∼0.6 V and sufficient current to charge capacitors of various capacitances (1 to 22 µF). The energy conversion efficiency of 42.93% ± 0.52% and power density of 11 nW/cm ² is achieved in device having 1.6 µm thick film, surpassing conventional AlN‐based PENGs that typically suffer from low output voltage and poor interface quality. Simultaneously, piezotronic sensing improves, with Schottky barrier modulation of ∼17.16 meV and gauge factor of ∼73.65 × 10 ³ . These results establish that thickness‐driven AlN‐based devices are a potential candidate for next‐generation self‐powered applications.