Dual Modulation of Dark Carrier and Photocarrier in Ga ₂ O ₃ Nanopillar Arrays for High‐Performance Solar‐Blind Ultraviolet Photodetectors

ABSTRACT Planar Ga 2 O 3 ‐based solar‐blind photodetectors (SBPDs) are limited by weak light absorption and elevated surface‐related dark current, impeding practical applications. Here, Ga 2 O 3 nanopillar‐integrated SBPDs are proposed to strengthen light‐matter interactions and suppress dark current through interfacial barrier modulation. The conduction band upshift increases the interfacial barrier and confines carrier transport channels, significantly reducing dark current, with its suppression modulated by the nanopillar period. The nanopillar geometry further enhances light absorption by reducing reflectance and transmittance while strengthening the local electric field. The nanoengineered structure fabricated via electron‐beam lithography and inductively coupled plasma etching exhibits improved absorbance and photoluminescence. The optimized SBPDs incorporating Ga 2 O 3 nanopillar arrays achieve a 1000‐fold reduction in dark current, a responsivity of 354.6 A/W, a specific detectivity of 4.21 × 10 14 Jones (an improvement of 2729.4%), and ultrafast response times of 0.29/0.35 ms (τ r /τ d ). Systematic investigation reveals the dual optimization mechanisms through enhanced light‐matter interactions and barrier‐controlled carrier transport. This work introduces an innovative strategy to advance the performance of Ga 2 O 3 ‐based SBPDs for future applications.