Synthesis and In-Situ TEM Transport Measurements of Individual GaN Nanowires and Nanotubes

High-purity GaN nanowires and nanotubes of various morphologies and sizes have been synthesized through epitaxial growth on [001]-oriented sapphire substrates. The GaN nanowires grown on Ni catalyst particles possess an average diameter of similar to 100 nm and rather smooth surface; whereas GaN nanotubes guided by Au particles exhibit large diameters (100 similar to 500 nm) and rough surface morphology. The microstructures and crystallography of GaN nanowires and nanotubes were analyzed using a high-resolution transmission electron microscope (HRTEM). For the first time the electrical transport in individual GaN nanowires and nanotubes was in-situ measured inside the microscope. The electrical transport was mainly affected by the nanocrystal quality and nanostructure/contact interfaces.