High-Performance Self-Driven Single GaN-Based p-i-n Homojunction One-Dimensional Microwire Ultraviolet Photodetectors

With the increasing global concern about energy consumption, self-driven photodetectors are especially attractive. In this paper, we prepared high-performance self-driven single GaN-based p-i-n homojunction onedimensional microwire ultraviolet photodetectors (UV PDs) with a vertical structure. High-quality trapezoidal GaN-based p-i-n homojunction micro wires were selectively heteroepitaxially grown on a patterned Si(100) substrate by metal organic chemical vapor deposition (MOCVD). The upper and lower electrodes were separated by simple spin-coating and photolithography. The single GaN-based p-i-n homojunction microwire UV PDs show outstanding self-driven performance under 325 nm light irradiation, including a low dark current (10 pA), a fast response speed (Tr = 1.12 ms/Td = 2.8 ms), and an excellent detectivity (1.30 x 10(12) jones). In addition, the UV PDs have a high responsivity (251 mA/W) at 0 V. The high performance of the UV PDs is mainly due to the wider built-in electric field formed in the p-i-n junction and vertical conductive structure with reduced dimensionality. This study not only provides a simple and feasible method to fabricate one-dimensional vertical-structured microwire UV PDs but also provides a basis for the subsequent fabrication of UV PDs with high-performance self-driven homojunctions.