No abstract

No abstract

Control of the diameter and pitch of InGaAs nanowire arrays in selective-area metalorganic vapor-phase epitaxy was investigated. It was found that their nucleation was strongly dependent on the geometry of the mask, resulting in the difficulty of nucleation for a larger mask pitch, particularly for an opening diameter of less than 50 nm. Precise adjustment of the V/III ratio enabled us to control the nucleation independently of the mask pitch for smaller openings, and we successfully obtained 30-nm-diameter InGaAs nanowires independently of the mask pitch by the proposing V/III-ratio-controlled two-step growth method. #

The authors report on the fabrication of MnAs/GaAs hybrid nanowires by combining selective-area metal–organic vapor phase epitaxy of GaAs nanowires and “endotaxy” of MnAs nanoclusters. MnAs nanoclusters are embedded in the six ridges of hexagonal GaAs nanowires as a result of endotaxy. From the cross-sectional characterizations by transmission electron microscopy, the average width of MnAs nanoclusters with the hexagonal NiAs-type crystal structure and the average depth in GaAs nanowires are estimated to be about 10 and 8 nm, respectively. The magnetic responses detected from the reference samples grown on planar GaAs (111)B layers show that ferromagnetic MnAs nanoclusters are formed. The diameter of nanoclusters grown in GaAs nanowires increases with decreasing growth temperature and/or increasing distance between the GaAs nanowires, while the density of nanoclusters increases with increasing growth temperature. It is found that the diameter and density of nanoclusters are strongly influenced by the gas supplied during the decrease in temperature after the nanocluster growth.

No abstract