Effects of growth interruption, As and Ga fluxes, and nitrogen plasma irradiation on the molecular beam epitaxial growth of GaAs/GaAsN core-shell nanowires on Si(111)

摘要

We investigate fundamental issues on the growth of GaAs/GaAsN core-shell heterostructure nanowires (NWs) by plasma-assisted molecular beam epitaxy. A Ga catalyst crystallizes during growth interruption at a high As pressure, and afterwards the growth dominantly progresses mainly increasing the NW diameter, thereby forming a wire shell. The shell diameter increases linearly depending on growth time and group Ⅲ flux, similarly to the growth mechanism of planar layers. The lateral growth rate is 0.19 times lower than the growth rate of planar GaAs on a (100) substrate. At a substrate temperature 570 ℃, nitrogen incorporation is inefficient in the shell layer. At a substrate temperature of 430 ℃, the nitrogen is effectively introduced under continuous plasma irradiation during the growth of the GaAsN shell, resulting in the introduction of nitrogen within the shell estimated up to about 0.5%.