Current rectification in a single GaN nanowire with a well-defined p–n junction

This letter discusses Mg incorporation in GaN nanowires with diameters ∼35 nm, fabricated by vapor–liquid–solid synthesis in p-type nanowires. Turning on the Mg doping halfway through the synthesis produced nanowires with p–n junctions that showed excellent rectification properties down to 2.6 K. The nanowires are shown to possess good-quality, crystalline, hexagonal GaN inner cores surrounded by an amorphous GaN outer layer. Most wires grow such that the crystalline c axis is normal to the long axis of the nanowire. The temperature dependence of the current–voltage characteristics is consistent with electron tunneling through a voltage-dependent barrier.