We report on the selective area growth (SAG) of GaAs
nanowires
(NWs) by the catalyst-free vapor-solid mechanism. Well-ordered GaAs
NWs were grown on GaAs(111)B substrates patterned with a dielectric
mask using hydride vapor phase epitaxy (HVPE). GaAs NWs were grown
along the ⟨111⟩B direction with perfect hexagonal shape
when the hole’s opening diameter in SiN
x
or SiO
x
mask was varied from 80
to 340 nm. The impact of growth conditions and the hole size on the
NW lengths and growth rates was investigated. A saturation of the
NW lengths was observed at high partial pressures of As4, explained by the presence of As trimers on the (111)B surface at
the NW top surface. By decreasing As4 partial pressure
and decreasing the hole size, high aspect ratio NWs were obtained.
The longest and thinnest NWs grew faster than a two-dimensional layer
under the same conditions, which strongly suggests that surface diffusion
of Ga adatoms from the NW sidewalls to their top contributes to the
resulting axial growth rate. These findings were supported by a dedicated
model. The study highlights the capability of the HVPE process to
grow high aspect ratio GaAs NW arrays with high selectivity.
In this work, we demonstrate the growth of vertically
oriented
GaAs nanowires (NWs) and microplatelets directly on a patterned SiO2/Si(111) substrate by hydride vapor-phase epitaxy (HVPE).
Direct condensation of GaAs on Si was achieved through a critical
surface preparation under an As-controlled atmosphere. GaAs NWs were
grown along the ⟨111⟩B direction with a hexagonal
cross section when the hole opening diameter (D)
in the SiO2 mask was below 350 nm. Larger apertures (D ≥ 500 nm) resulted in uniform microplatelets. This
study highlights the capability of HVPE for selective area growth
of GaAs directly on Si and thus the potential of HVPE as a generic
heterointegration process for III–V semiconductors on silicon.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.