Formation of GaAs/GaSb Core-Shell Heterostructured Nanowires Grown by Molecular-Beam Epitaxy

Abstract

Abstract:In this paper, we demonstrated the growth of GaAs/GaSb core-shell heterostructured nanowires on GaAs substrates, with the assistance of Au catalysts by molecular-beam epitaxy. Time-evolution experiments were designed to study the formation of GaSb shells with different growth times. It was found that, by comparing the morphology of nanowires for various growth times, lateral growth was taking a dominant position since GaSb growth began and bulgy GaSb particles formed on the nanowire tips during the growth. The movement of catalyst Au droplets was witnessed, thus, the radial growth was enhanced by sidewall nucleation under the vapor-solid mechanism due to the lack of driving force for axial growth. Moreover, compositional and structural characteristics of the GaAs/GaSb core-shell heterostructured nanowires were investigated by electron microscopy. Differing from the commonly anticipated result, GaSb shells took a wurzite structure instead of a zinc-blende structure to form the GaAs/GaSb wurzite/wurzite core-shell heterostructured nanowires, which is of interest to the research of band-gap engineering. This study provides a significant insight into the formation of core-shell heterostructured nanowires.

Self-Powered Photodetectors Based on Core–Shell ZnO–Co3O4 Nanowire Heterojunctions

“…HR-TEM micrographs (Figure a,b) of the NWs display a rough surface because of the presence of pyramidal-like nanocrystallites, whose lattice planes are characterized by the typical d -spacing of Co 3 O 4 . The nanocrystals seem not to have a preferential orientation, but the presence of Moiré pattern only on the ZnO–Co 3 O 4 sample in the absence of Al 2 O 3 might be due to the strain induced by a quasi-epitaxial growth of the core–shell structure . On the other hand, the sample containing alumina is characterized by a sharper interface.…”

Growth and Strain Relaxation Mechanisms of InAs/InP/GaAsSb Core-Dual-Shell Nanowires

“…One of the most appealing NW features is the possibility to create heterostructures by combining different materials in both axial and radial directions. , In recent years, researchers have been paying much attention to the so-called core–shell (CS) NWs because radial geometry can improve the performance and/or add new properties in the devices. , For example, surface passivation by the introduction of one or more shells around the core can enhance the radiative emission efficiency, reducing the carrier surface recombination . Many core–shell NWs based on III–V semiconductors have been demonstrated: InAs/InP, InAs/GaAs, InAs­(Sb)/GaSb, InAs/GaSb, and GaAs/GaSb . Among these, InAs/GaSb core–shell NWs have attracted a great deal of attention because of their peculiar properties that provide a useful platform for many applications.…”

“…6 Many core−shell NWs based on III−V semiconductors have been demonstrated: InAs/InP, 7 InAs/GaAs, 8 InAs(Sb)/GaSb, 6 InAs/GaSb, 9 and GaAs/GaSb. 10 Among these, InAs/GaSb core−shell NWs have attracted a great deal of attention because of their peculiar properties that provide a useful platform for many applications. As a matter of fact, both InAs and GaSb have very small effective masses with high electron and hole mobility, respectively.…”