Rapid-sensitive, UV photodetectors based on rGO-wrapped vertically aligned GaN nanowire heterostructures

Wafer-scale, vertically grown GaN nanowire array (NW-A) integrated with reduced graphene oxide (rGO) hybrid heterostructure presents a significant advancement in ultraviolet (UV) photodetectors, offering a compact design with enhanced sensitivity and reliability. In this work, we demonstrate a simple, scalable spin-coating method for depositing a highly conductive 2D rGO nanolayer onto vertically integrated n -GaN NW-A grown on a Si substrate. This process establishes a van der Waals (vdW) Schottky junction, which plays a crucial role in enhancing the performance of UV sensing. The built-in electric field at the vdW Schottky interface facilitates efficient charge-carrier separation, resulting in a significantly improved UV photoresponse compared to a pristine n-GaN NW-A. Notably, the rGO: n -GaN NW-A heterostructure on Si photodetector exhibits a 3-fold enhancement in photoresponsivity (74.5 μA/W at 2V) compared to the n -GaN NW-A device (22.6 μA/W at 2V), highlighting its potential for next-generation high-performance UV photodetection applications.