Aligned AlN nanowires by self-organized vapor-solid growth

Area of Science:

• Materials Science
• Nanotechnology
• Crystal Growth

Background:

• Single crystal aluminum nitride (AlN) nanowires are promising for electronic and optoelectronic applications.
• Controlled synthesis of highly oriented AlN nanowires is crucial for device fabrication.
• Understanding the vapor-solid growth mechanism is essential for optimizing nanowire properties.

Purpose of the Study:

• To synthesize highly oriented AlN single crystal nanowires.
• To investigate the growth mechanism of AlN nanowires via a vapor-solid approach.
• To explore the influence of substrate and growth conditions on nanowire morphology and structure.

Main Methods:

• Vapor-solid synthesis at 1750°C and 850 mbar nitrogen pressure.
• Utilized vicinal SiC substrates pretreated by SiC sublimation epitaxy.
• Characterized nanowire dimensions, orientation, and crystal structure.

Main Results:

• Synthesized highly oriented AlN nanowires with aspect ratios up to 600, diameters of 40-500 nm, and lengths of 100 µm.
• Observed a change in nanowire thickness after reaching critical length, providing insights into growth mechanisms.
• Achieved perfect alignment along the [0001] direction with hexagonal cross-sections and dislocation-free wurtzite structures.
• Demonstrated preferential c-axis growth under nitrogen excess, switching to lateral growth below critical nitrogen pressure.

Conclusions:

• The study successfully synthesized highly oriented AlN nanowires with controlled dimensions and alignment.
• The observed thickness change offers a new understanding of the AlN nanowire growth mechanism.
• The findings pave the way for potential applications of these high-quality AlN nanowires in advanced electronic devices.