Temperature-dependent side-facets of GaAs nanopillars

In this study, the effect of growth temperature on the structural properties of Au-catalysed epitaxial GaAs semiconductor nanopillars grown by metal-organic chemical vapour deposition is investigated by electron microscopy. It has been found that the growth temperature plays a significant role on the evolution of side-facets of zinc-blende structured GaAs nanopillars. At a growth temperature of 550 °C, six $\left\{112\right\}$ side-facets are formed; whereas at a higher growth temperature of 600 °C, six $\left\{110\right\}$ side-facets are observed. It is believed that the formation of $\left\{112\right\}$ side-facets is a kinetically dominated process while the formation of $\left\{110\right\}$ side-facets is a thermodynamical process. Besides, the diffusion-induced nanopillar foundations present the same $\left\{112\right\}$ edge side-facets regardless of the growth temperature. (paper)