Growth of n-doped GaAs nanowires by Au-assisted metalorganic chemical vapor deposition: Effect of n-type dopants flux rates

Three samples of GaAs NWs grown with different n-type dopants flux rates were researched. From SEM figures, we can find that all NWs are vertical to the substrate and no lateral growth occurs. The growth rate is proportional the flux rates of n-type dopant SiH4. Larger SiH4 flux rate results in larger growth rate of NWs. For n-doped NWs, their growth were affected by Gibbs-Thomson effect, which is that NWs with larger diameters grow faster than those with smaller diameters. For all samples, the contribution from adatom diffusion can be negligible and almost all contribution comes from catalytic pyrolysis of the precursors impinging on the NPs. From TEM images, pure zinc blende structures without any stacking faults from bottom to top for all three samples were achieved. This study on n-doped GaAs NWs have many potential applications for nano-electronic and nano-optoelectronic devices.