Ga₂O₃@Al₂O₃ Core–Shell Nanowires for High-Performance Solar-Blind Photodetectors

Abstract

High-performance solar-blind photodetectors (SBPDs) have been indispensable in both military and civilian applications. Herein, Ga2O3@Al2O3 core–shell nanowires (NWs) are synthesized by plasma-enhanced atomic layer deposition (PEALD) Al2O3 layer on the surface of Ga2O3 nanowires. The Ga2O3@Al2O3 NW has a length of tens of micrometers, and the thickness of Ga2O3 and Al2O3 layers in the NW is approximately 30 and 5 nm, respectively. The PEALD method passivates surface defects to improve the crystal quality of Ga2O3. The metal–semiconductor–metal (MSM) Ga2O3@Al2O3 NW-based SBPDs exhibit a superhigh sensitivity of 1.07 × 103 A/W and a high response speed of less than 83 ms at 5 V bias voltage under 254 nm irradiation. Additionally, the Ga2O3@Al2O3 NW PDs exhibit a superhigh specific detectivity of 3.38 × 1011 Jones, an external quantum efficiency (EQE) of 5.22 × 105%, and a high deep ultraviolet (DUV)/visible responsivity rejection ratio (R254/405) of 4.81 × 102. These results suggest that this method is an effective way to design and prepare high-performance photonic devices.