Point Defect Induced Potential Wells across the m‐Plane of Core/Shell GaN Nanowires

Nanowires are promising structures for next‐generation photonic devices due to their superior structural, optical, and electronic properties compared to thin films. In this study, unexpected electrostatic potential wells across the non‐polar m ‐plane and at the core/shell interface in n‐type GaN core/shell nanowires, grown via metal‐organic vapor phase epitaxy, are reported. Using advanced electron microscopy, including off‐axis electron holography, electrostatic potential distributions are mapped and shallow quantum wells are identified at the core/shell interface and core center. High‐resolution transmission electron microscopy ruled out planar and line defects, implicating point defects as their source. Valence electron energy loss spectroscopy revealed localized bandgap narrowing due to strain from concentrated point defects. Hyperspectral cathodoluminescence linked lower potential in the core to C N defects, while the absence of related luminescence at the core/shell interface suggests V Ga O N defect complexes as plausible causes. These findings highlight the critical role of point defects in GaN nanowires, with significant implications for device performance.