Temperature Evolution of Gallium Nitride Nanowire Vapor-solid Growth Matrix

Recent results indicate that vapor-solid growth mechanisms can yield semiconductor nanowires with high crystallinity. In the present experiments, gallium nitride nanowire growth is initiated following formation of a microcrystalline growth matrix. A change in nanowire orientation from wurtzite $<$2-1-10$>$/zinc-blende $<$011$>$ directions at 850\r{ }C and 950\r{ }C to the wurtzite [0001] direction at 1000\r{ }C is observed. The change in nanowire orientation is correlated with changes in the growth matrix. Investigations of the evolution of the growth matrix as a function of temperature using x-ray diffraction with orientation analysis, atomic fore microscopy, high-resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM) are presented.