GaN nanowire and Ga2O3 nanowire and nanoribbon growth from ion implanted iron catalyst

The authors experimentally demonstrate a simple and efficient approach for nucleating the catalytic chemical vapor deposition CVD growth of GaN nanowires, Ga2O3 nanowires, and Ga2O3 nanoribbons by using ion implantation of Fe+ into thermally grown SiO2 layers and subsequent annealing to form the catalyst nanoparticles. This work shows that ion implantation can be used as a versatile method to create catalyst nanoparticles for wide band gap nanowire/nanoribbon growth. They also demonstrate that ion implanted catalyst nanoparticles prepared under identical conditions can be used to grow different types of nanowires/nanoribbons containing Ga by simply changing the gas types and flow rates during CVD growth. Furthermore, they systematically characterize the structural properties of the as-grown nanomaterials, and find that the distance between the Ga source and the substrate, growth temperature, growth time, and flow rates are all critical parameters for nanowire growth. They explain the growth of single-crystal wurtzite GaN and monoclinic -Ga2O3 nanowires by the vapor-liquid-solid VLS growth model, whereas the growth of monoclinic -Ga2O3 nanoribbons by a combination of the VLS and vapor-solid VS mechanisms. This work opens up the possibility of controlling the origin of wide band gap nanowires/nanoribbons at the nanometer scale using the technique of catalyst ion implantation through a lithographically defined mask, of integrating nanowires/nanoribbons into nonplanar three-dimensional device structures, and of growing different Ga-based wide band gap semiconductor nanostructures on the same substrate by simply changing the gas types and flow rates. © 2008 American Vacuum Society. DOI: 10.1116/1.2993175