High-performance shortwave deep-UV response-enhanced photodetector based on nanoporous AlGaO/AlGaN with efficient light-harvesting

Abstract

In this article, a photodetector (PD) based on nanoporous (NP) AlGaO/AlGaN with efficient light capture and enhanced shortwave deep-UV (DUV) response has been demonstrated. A controllable electrochemical etching was utilized to obtain the NP-AlGaN with an extremely low reflectivity and a strong coupling absorption. After thermal oxidation, the NP-AlGaN was converted into NP-AlGaO, which can significantly suppress the dark current for the fabricated PD, resulting in a detectivity of up to 1.5 × 10¹³ Jones at 5 V. Meanwhile, defect passivation during oxidation significantly enhances its response speed (6–7 μs), contributing to a high gain-bandwidth product of 2.6 × 10⁵. Critically, the NP-AlGaO/AlGaN hybrid structure greatly improves the responsivity for the shortwave DUV band and the high penetration confers the PD with even better detection capability in the wider DUV band. Therefore, the proposed device manipulating photon motion by means of novel nano-optical structures has great prospects for the detection of weak optical signals in the wide DUV spectral range, also opening up great opportunities for high-sensitivity sensors based on the nanostructured semiconductors.