Axial InAs/GaAs heterostructures on silicon in a nanowire geometry

Area of Science:

• Materials Science
• Semiconductor Growth
• Epitaxy

Background:

• Semiconductor islands on silicon substrates are crucial for advanced electronic devices.
• Controlling the growth of different semiconductor materials on these islands presents significant challenges.
• Indium arsenide (InAs) on gallium arsenide (GaAs) heterostructures are of interest for optoelectronic applications.

Purpose of the Study:

• To systematically explore growth parameters for depositing InAs onto GaAs islands on silicon.
• To identify conditions favoring selective InAs growth on GaAs and purely axial growth.
• To characterize the structural properties of the resulting InAs/GaAs heterostructures.

Main Methods:

• Droplet epitaxy was used to create initial GaAs islands on a silicon substrate.
• Systematic variation of deposition parameters for InAs growth.
• Synchrotron X-ray diffraction was employed for structural analysis.

Main Results:

• Selective growth of InAs on GaAs islands was achieved under specific conditions.
• Purely axial growth of InAs segments was realized, forming structures rotated by 30° relative to the GaAs base.
• InAs segments were found to be grown relaxed on GaAs, exhibiting a predominantly zincblende crystal structure with stacking faults.

Conclusions:

• Precise control over InAs growth on GaAs islands on silicon is achievable.
• The study provides insights into the formation of rotated axial InAs segments.
• The relaxed growth and structural characteristics of InAs/GaAs on silicon are elucidated.