High-performance piezotronic pressure sensor synergistically modulated by structural densification and piezopotential

Abstract Developing flexible pressure sensors that combine ultrahigh sensitivity with dynamic structural adaptability is crucial for advancing next-generation tactile perception and human-machine interfaces. However, achieving the synergistic modulation of macroscopic geometric configurations and microscopic interfacial energy bands within a single device remains a formidable challenge. Herein, we develop a high-performance piezotronic pressure sensor based on a p-GaN/3D sea-urchin-like n-ZnO microsphere heterojunction architecture. The exceptional performance of the device originates from a cross-scale synergistic dual-modulation mechanism. Macroscopically, applied mechanical stress drives physical densification of the loose ZnO core-spike network, significantly expanding carrier transport pathways within the matrix. Microscopically, the strain-induced local piezopotential in p-GaN modulates the heterojunction interfacial barrier, thereby enabling exponential amplification of cross-interface carrier injection. Driven by the profound mechano-electronic coupling at the interface, the device delivers an exceptional current modulation ratio of up to 5.59×103 under a 1.5 V bias. Furthermore, it achieves an ultrahigh pressure sensitivity of approximately 83.9 mV/MPa in the low-pressure regime, alongside extraordinary anti-fatigue reliability over 7200 s of continuous high-frequency dynamic loading. This work provides a novel perspective for tuning piezotronic carrier dynamics using hierarchical micro/nanostructures, laying a solid foundation for the development of next-generation smart tactile interfaces.