Enhanced Photoresponse Performance of Self‐Powered PTAA/GaN Microwire Heterojunction Ultraviolet Photodetector Based on Piezo‐Phototronic Effect

Abstract The development of self‐powered high‐performance UV photodetectors is essential for energy efficient futuristic wearable and portable applications. Herein, a self‐powered organic/inorganic (PTAA/GaN microwire) hybrid heterojunction ultraviolet (UV) photodetector (PD) has been prepared by a low‐cost and simple spin‐coating method. Furthermore, the piezo‐phototronic effect as an effective interfacial regulating strategy is utilized to modulate the photo‐response performances of the PD by engineering the energy‐band structure at the local junction/interface. Under 325 nm laser irradiation, the obtained device demonstrates excellent photo‐response properties at 0 V bias, showing a high responsivity (268 mA W⁻¹) and detectivity (2.49 × 10¹² Jones) under weak light intensity as low as 0.2 mW cm⁻², as well as fast response speeds (rise time of 14 ms and decay time of 23 ms). The PD exhibits better performance than most reported organic/inorganic heterojunction self‐powered PDs. By applying a −0.52% compressive strain, the responsivity and detectivity of the device are greatly enhanced by 32% without external bias, and by 1256% at 2 V bias under 1.4 mW cm⁻² light intensity. On the contrary, by applying a 0.41% tensile strain, the responsivity and detectivity are decreased by 18% without external bias. It indicates that the strain has a significant modulating effect on the photo‐response performance of the PD. The positive piezo‐potential modulated energy‐band structure at the PTAA/GaN interface may account for the enhanced performance. This study demonstrates a promising approach to optimize the performance of a self‐powered heterostructure optoelectronic devices through strain modulated.