Self-assembly ZnO mesh and GaN heterojunction voltage sensitive ultraviolet photodetector

While ZnO/GaN heterojunction UV photodetectors are widely studied-there is scope for improvement in their performance. This paper proposes a method using self-assembled SiO2microspheres as a mask to fabricate a ZnO mesh and GaN heterojunction self-powered ultraviolet (UV) detector via chemical vapor deposition (CVD), resulting in a device with a lower dark current and faster response time. The voltage response measurement approach was selected to mitigate the impact of dark current noise under low light power irradiation. Introducing of the ZnO mesh structure considerably enhances the weak-light detection capabilities and response time of the detector, thus-achieving self-powered UV detection under weak-light conditions, attributed to the dense and orderly arrangement of the SiO2microsphere array, which introduces periodic structural defects and oxygen vacancies during the growth of ZnO, reducing carrier recombination and extending their lifetime. Additionally, the larger specific surface area of the mesh structure improves the light absorption efficiency, thereby enhancing the responsivity and detectivity. At zero bias voltage and 355 nm, the responsivity reached 2200 V/W, respectively, while the response time improved from 3.14 ms to 392 mu s. These results demonstrate that the fabricated self-powered device exhibits significantly high responsivity and the ability to detect weak light signals, thus proving the potential value of using self-assembled mesh structures for fabricating UV photodetectors.