GaAs nanowires with oxidation-proof arsenic capping for the growth of an epitaxial shell

Abstract

We propose an arsenic-capping/decapping method, allowing the growth of an epitaxial shell around the GaAs nanowire (NW) core which is exposed to an ambient atmosphere, and without the introduction of impurities. Self-catalyzed GaAs NW arrays were firstly grown on Si(111) substrates by solid-source molecular beam epitaxy. Aiming for protecting the active surface of the GaAs NW core, the arsenic-capping/decapping method has been applied. To validate the effect of this method, different core/shell NWs have been fabricated. Analyses highlight the benefit of the As capping-decapping method for further epitaxial shell growth: an epitaxial shell with a smooth surface is achieved in the case of As-capped-decapped GaAs NWs, comparable to the in situ grown GaAs/AlGaAs NWs. This As capping method opens a way for the epitaxial growth of heterogeneous material shells such as functional oxides using different reactors.

GaAs Core/SrTiO3 Shell Nanowires Grown by Molecular Beam Epitaxy

“…42 The As capping layer was grown by the deposition of As 2 at room temperature for 120 min. The diffraction pattern was in accordance with an amorphous As capping layer (further details concerning the As capping and decapping can be found in ref 54).…”

“…However the epitaxial growth of perovskite oxides on III-V NWs is still rather challenging. By the As capping / decapping method (Figure 1a), the GaAs NWs (or GaAs / AlGaAs NWs) could be transferred among different separated reactors without oxidizing or contaminating the GaAs (or AlGaAs) facets [3], which is of great necessity for the further functional oxide shell growth. Then, by means of the twosteps SrTiO 3 growth method [4], we have obtained a partially oriented SrTiO 3 shell covering the GaAs NWs (Figure 1b), proving the possibility to fabricate the monocrystalline epitaxial shell of functional oxides integrated on semiconducting NWs [5].…”

Observing visible-range photoluminescence in GaAs nanowires modified by laser irradiation

“…31 For power density of 1.4 MW/cm 2 , the nanowire temperature reaches ~ 700 K, that is enough to evaporate the arsenic layer from the nanowire surface. 32 Now we discuss the effect of compositional and structural changes in nanowires on their PL spectra. Fig.…”

X-ray photoelectron spectroscopy study of Ga nanodroplet on silica-terminated silicon surface for nanowire growth

“…In this part we have replicated the early stages of standard NW growth conditions 14,25,26 : Ga was deposited at a substrate temperature of 510 °C and the substrate temperature was then increased to reach the temperature at which GaAs NWs are grown. This post-deposition annealing has been performed between 560 °C and 660 °C.…”