Interaction between lamellar twinning and catalyst dynamics in spontaneous core-shell InGaP nanowires

Area of Science:

• Materials Science
• Nanotechnology
• Semiconductor Physics

Background:

• Semiconductor nanowires (<211> orientation) often exhibit twins, creating dual {111} facets.
• Group IV nanowires have equivalent {111} facets, while III-V nanowires have polar facets.
• Maintaining <211> orientation in III-V nanowires requires balanced growth rates between polar facets.

Purpose of the Study:

• To report the observation of stable, micron-long <211>-oriented InGaP nanowires.
• To investigate the formation of spontaneous core-shell structures in these nanowires.
• To understand the mechanisms governing nanowire stability, branching, and stress generation.

Main Methods:

• Growth of <211>-oriented Indium Gallium Phosphide (InGaP) nanowires.
• In-situ observation of catalyst behavior during sample cool-down.
• Analysis of crystal structure, including stacking faults and facet polarities.
• Characterization of core-shell structure and stress distribution.

Main Results:

• Stable, micron-long <211>-oriented InGaP nanowires with a spontaneous core-shell structure were observed.
• Stacking fault formation at the {111}A facet provides a stable nanowire/nanoparticle (NW/NP) interface for <211> growth.
• Catalyst migration to a {111}B facet during cooling induces perpendicular branching.
• The core-shell structure is non-concentric, leading to stress and nanowire bending.

Conclusions:

• Stacking faults are crucial for stabilizing <211> growth in InGaP nanowires.
• Catalyst migration and facet asymmetry drive complex structural evolution, including branching and stress.
• The observed phenomena offer insights into controlling nanowire morphology and properties for advanced applications.