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

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 × 10 12 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.