Hydrogen‐Plasma‐Enabled Ultrafast p‐GaN/AlGaN/GaN Hybrid Anode Diode for Visible‐Blind Near‐Ultraviolet Photodetection

We demonstrate a visible‐blind near‐ultraviolet (near‐UV) photodetector based on a hydrogen‐plasma‐treated two‐terminal p‐GaN‐gated hybrid‐anode diode. In the dark, the p‐GaN optical gate depletes the AlGaN/GaN two‐dimensional electron gas (2DEG), yielding a dark current of 6.82 × 10 ⁻⁹  mA/mm (normalized to gate width). Under 365‐nm illumination, 2DEG recovery increases the photocurrent to 12.99 mA/mm and yields a 365‐nm responsivity of 7.7 × 10 ³  A/W. Enabled by an etch‐free gate‐definition HPT process that mitigates trap‐assisted effects, the device exhibits rise and fall times of 22.96 and 167.87 μs, respectively. These results indicate that the HPT‐enabled HAD combines low dark current, high responsivity, and microsecond‐scale response for GaN‐based near‐UV photodetection.