CRYSTALLOGRAPHIC ALIGNMENT OF HIGH-DENSITY NANOWIRE ARRAYS

摘要

A method for controlling the crystallographic growth direction and geometric and physical characteristics of nanowires using a metal-organic chemical vapor deposition and substrate selection. As an illustration of the method, epitaxial growth of wurtzite gallium nitride on (100) y -LiAIOSUB2/SUB and (111) MgO single crystal substrates resulted in the selective growth of nanowires in the orthogonal [110] and [001] directions, respectively. Triangular and hexagonal cross sections were observed as a result of substrate-induced constraints of lattice parameter matching and symmetry registry. These nanowire arrays exhibit a systematic difference in their temperature­ dependent band-edge emission resulting from the different size, shape, and anisotropic polarity of the nanostructures. Scaling of the synthetic process is entirely compatible with existing GaN thin-film technology and should enable the realization of a new generation of GaN nanowire devices and systems.