Self-formed core–shell InGaN nanowires: A dual-functional platform for persistent photoconductivity and self-driven photodetection

We report self-formed core–shell InGaN nanowires (NWs) grown by plasma-assisted molecular beam epitaxy on p-Si (111) substrates, which exhibit dual functionalities: persistent photoconductivity (PPC) and self-driven photodetection at 0 bias. The core–shell structure (In-rich core: 55% In, 2.05 eV; In-poor shell: 12% In, 2.76 eV) is optimized by a SiNx passivation layer, which suppresses surface defects, stabilizes the NW/substrate interface, and enables Fowler–Nordheim tunneling-dominated carrier transport. For self-driven photodetection, the NWs achieve a peak response at 520 nm (matching the core bandgap) with a responsivity of 0.8 mA/W, a detectivity of 6 × 107 Jones, and external quantum efficiency superior to most InGaN-based self-driven detectors. The PPC effect, originating from two types of DX centers (in core and shell) with electron redistribution, shows a bi-exponential decay (τ1 = 0.42 s and τ2 = 3.78 s) under 395 nm illumination. The SiNx passivation ensures reproducible PPC decay and stable photodetection performance, confirming the NWs as a promising dual-functional platform for low-power optoelectronic applications.