Coarsening effect on island-size scaling: the model case InAs/GaAs(001)

Area of Science:

• Materials Science
• Surface Science
• Nanotechnology

Background:

• Island size and capture zone distributions are key parameters in nucleation and growth processes.
• Understanding these distributions is vital for controlling thin film morphology and properties.
• Coarsening significantly impacts these distributions, but its precise effect requires detailed investigation.

Purpose of the Study:

• To comparatively analyze island size and capture zone distributions.
• To investigate the influence of coarsening on these distributions during nucleation.
• To validate numerical simulations against experimental observations.

Main Methods:

• Experimental growth of Indium Arsenide (InAs) islands on Gallium Arsenide (GaAs(001)) substrates.
• Manipulation of coarsening by varying substrate temperature during experiments.
• Two-dimensional kinetic Monte Carlo simulations considering single-species diffusing adatoms.
• Modification of binding energy between adatoms and islands in simulations to alter coarsening.

Main Results:

• Island size and capture zone distributions were found to overlap exclusively when coarsening effects were absent or negligible.
• Experimental results demonstrated the impact of temperature on the coarsening process.
• Simulations confirmed that altering adatom binding energy effectively controlled coarsening.

Conclusions:

• Coarsening is a critical factor that differentiates island size and capture zone distributions.
• The overlap of these distributions serves as an indicator for the absence of coarsening.
• The study provides a framework for understanding and predicting thin film growth dynamics.