Geometry-asymmetry-induced instability of tunneling current in core–shell nitride prism nanowires

Group III nitride core–shell nanowire resonant tunneling diodes show great potential for high-frequency and low-power nanoelectronic devices, as they can effectively suppress threading dislocations caused by lattice mismatch through elastic strain relaxation. However, experimentally synthesized wurtzite AlGaN core–shell nanowires exhibit pronounced tunneling current instability, which greatly limits their practical applications. Here, we show that this instability arises from the in-plane anisotropy of prismatic core–shell nanowires, which induces multiple tunneling current peaks, as revealed by our calculated current–voltage characteristics. Such in-plane anisotropy is often overlooked in theoretical and experimental analyses because nanowires are typically modeled as cylindrical, even though prismatic cross sections are a common feature of wurtzite nitride nanowires. We further demonstrate that this anisotropy-induced multi-peak behavior can be eliminated through appropriate design of the Al composition and layer thickness, thereby improving the stability of the tunneling current.