Photo-response enhancement in longitudinal porous GaN-based UV

Gallium nitride (GaN), as a typical wide bandgap semiconductor, is an excellent candidate to fabricate the high-performance UV photodetector, due to its excellent intrinsic nature. However, the weak light absorption of conventional bulk GaN limits the further improvement of photo-response of GaN-based photodetectors. Here, we have prepared a longitudinal porous GaN using a simple electrochemical etching process, and then fabricated a porous GaN-based photodetector (Porous PD). The photo-response in the Porous PD has been improved significantly compared to the control planar GaN-based photodetector (Planar PD). At −1.2 V, the photo current (I_photo) in the Porous PD is ∼ 75 times higher than that of Planar PD, and the maximum responsivity of the Porous PD can reach 3.11 × 10⁴ A/W, which is attributed to the large internal gain (> 1.06 × 10⁵). The maximum specific detectivity of the Porous PD has also been calculated to be 5.22 × 10¹³ Jones, two orders of magnitude higher than that of the Planar PD. Our work paves the way to develop high-performance GaN-based PDs for detecting weak optical signals.