Aluminum Oxide-Assisted Ga2O3 Nanostructures for Enhanced Solar-Blind Ultraviolet Photodetection

Abstract This study presents a nanostructure design strategy based on the functional integration of anodic aluminum oxide (AAO). Unlike the conventional use of AAO as a sacrificial template, it is directly retained as a functional substrate, preserving both its structural integrity and functional advantages. Using atomic layer deposition (ALD), Ga2O3 is deposited in three forms: thin films, nanopillar arrays, and nanopore arrays. Compared with thin-film device, the nanostructured devices exhibit significantly enhanced photoresponse. In particular, the nanopore device achieves a responsivity of 87 A/W, which is approximately 6 times higher than that of the thin-film device, together with an external quantum efficiency of 4.25 × 104%, and a detectivity of 1 × 1014 Jones. The performance enhancement is mainly attributed to the following mechanisms: the retained AAO template enhances ultraviolet absorption through light scattering and localized electromagnetic field effects; Meanwhile, its high specific surface area strengthens the regulation of oxygen adsorption/desorption, thereby modulating the depletion layer and Schottky barrier, and optimizing carrier transport behavior. This work demonstrates that transforming AAO from a “sacrificial template” into a “functional structural unit” provides a simple and effective strategy for designing high-performance solar-blind ultraviolet photodetectors.