Interface-Driven Growth Mode Control of 2D GaSe on 3D GaAs Substrates with Distinct Crystallographic Orientations

Area of Science:

• Materials Science
• Surface Science
• Semiconductor Physics

Background:

• Previous studies on 2D gallium selenide (GaSe) growth via molecular beam epitaxy (MBE) on gallium arsenide (GaAs) substrates show varied outcomes.
• Reported differences in growth morphology, polytype, and interface characteristics necessitate a deeper understanding of substrate influence.

Purpose of the Study:

• To reexamine the growth mechanism of 2D GaSe on GaAs substrates with (211)B and (001)B orientations.
• To investigate the 2D/3D interface and its effect on 2D GaSe film morphology.
• To explore the impact of varied GaAs substrate surface preparation methods on GaSe growth.

Main Methods:

• Molecular beam epitaxy (MBE) for 2D GaSe film deposition.
• Varied preparation techniques for GaAs substrate surfaces.
• Analysis of 2D/3D interface characteristics and resulting GaSe film morphology.

Main Results:

• Identified the mechanistic origin of tilted versus non-tilted 2D growth.
• Established a general interface-driven orientation selection rule connecting substrate symmetry and dangling-bond coordination.
• Demonstrated a pathway for deterministic control over layered chalcogenide heterostructures.

Conclusions:

• Substrate interface engineering is crucial for controlling 2D GaSe growth morphology and orientation.
• The developed framework enables scalable integration of layered chalcogenide heterostructures with semiconductor platforms.
• This research provides a fundamental understanding for optimizing 2D material growth on dissimilar substrates.