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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 microwires 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 (T r = 1.12 ms/T d = 2.8 ms), and an excellent detectivity (1.30 × 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.

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By using the plasma enhanced chemical vapor deposition (PECVD) technique, amorphous silicon oxide films containing nanocrystalline silicon grain (nc-SiO x :H) are deposited, and the bonding configurations and optical absorption properties of the films are investigated. The grain size can be well controlled by varying the hydrogen and oxygen content, and the largest size is obtained when the hydrogen dilution ratio R is 33. The results show that the crystallinity and the grain size of the film first increased and then decreased as R increased. The highest degree of crystallinity is obtained at R = 30. The analyses of bonding characteristics and light absorption characteristics show that the incorporation of hydrogen leads to an increase of overall bonding oxygen content in the film, and the film porosity first increases and then decreases. When R = 30, the film can be more compact, the optical absorption edge of the film is blue shifted, and the film has a lower activation energy.