Postgrowth Shaping and Transport Anisotropy in Two-Dimensional InAs Nanofins

Area of Science:

• Materials Science
• Nanotechnology
• Semiconductor Physics

Background:

• Two-dimensional (2D) nanostructures are crucial for next-generation electronics.
• Indium arsenide (InAs) is a promising material for high-performance devices.
• Understanding transport properties in 2D nanostructures is essential for device optimization.

Purpose of the Study:

• To investigate the postgrowth shaping of free-standing 2D InAs nanofins.
• To explore the impact of wurtzite/zincblende polytypism on transport anisotropy in 2D InAs nanostructures.
• To demonstrate a method for fabricating complex nanostructures for device applications.

Main Methods:

• Selective-area epitaxy for growing 2D InAs nanofins.
• Citric acid-based wet etching for postgrowth shaping into complex geometries (e.g., van der Pauw cloverleaf).
• Mechanical transfer of nanofins to a separate substrate for device fabrication and characterization.

Main Results:

• Achieved complex nanofin shapes with patterning resolution down to 150 nm.
• Demonstrated partial thinning of nanofins to enhance local gate response.
• Observed a mobility anisotropy of order 2-4 at room temperature in 2D InAs nanofins.
• Attributed the anisotropy to polytypic stacking faults (wurtzite/zincblende).

Conclusions:

• Postgrowth shaping enables precise control over 2D InAs nanofin geometry and device functionality.
• Wurtzite/zincblende polytypism in 2D InAs nanostructures leads to measurable transport anisotropy.
• This study highlights the importance of materials considerations for self-assembled 2D III-V nanostructures in advanced epitaxy.