Internal Structures of Gallium Nitride Nanowires and Effects in Nanoelectronics

Catalyst-free vapor-solid nanowire growth is under investigation by several research groups, as it can result in higher crystalline quality compared with traditional vapor-liquid-solid growth. Our group has demonstrated that new nanowire orientations and multiphase relationships are also enabled1,2,3. These are strongly influenced by growth temperature, which is known to affect constituent atom kinetics. In vapor-solid growth, our group has demonstrated that it also affect nucleation site formation and availability. The types of nanowires that form and the corresponding nucleation sites over the growth temperature range 850-1000°C will be discussed. Multiphase nanowires typically form at 850-950°C with 112 0 [ ] wurtzite and 011 [] zinc blende domains that extend the full length of the nanowire. High-resolution transmission electron microscopy (HRTEM) of cross-sections created with focused ion beams (FIB) has demonstrated the presence of totally coherent interfaces between the wurtzite and zinc blende phases within these nanowires. New nanoscale ledges on growth matrix platelets have been indentified as potential nucleation sites. By 1000°C, nanowire growth orientation changes, an