Mass transport model for semiconductor nanowire growth

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Metal-particle-assisted growth is a key method for fabricating nanowires.
• Understanding factors influencing nanowire dimensions is crucial for their application.
• III/V semiconductor nanowires exhibit unique length-diameter relationships.

Purpose of the Study:

• To develop a mass transport model for nanowire growth based on surface diffusion.
• To explain the observed inverse relationship between nanowire diameter and length in III/V materials.
• To validate the model with experimental data and assess the significance of the Gibbs-Thomson effect.

Main Methods:

• Development of a theoretical mass transport model focusing on surface diffusion.
• Experimental growth of gallium phosphide (GaP) nanowires using metal-organic vapor phase epitaxy (MOVPE).
• Comparison of model predictions with experimentally measured nanowire lengths and radii.

Main Results:

• The surface diffusion model successfully explains why thinner III/V nanowires are typically longer than thicker ones.
• Experimental results for GaP nanowires align well with the model's predictions.
• The Gibbs-Thomson effect was found to be negligible for III/V nanowires under conventional growth temperatures and pressures.

Conclusions:

• Surface diffusion is a dominant mechanism governing mass transport in metal-particle-assisted nanowire growth.
• The developed model provides a valuable tool for predicting and controlling nanowire dimensions.
• The findings simplify the understanding of III/V nanowire growth, highlighting the limited impact of the Gibbs-Thomson effect in typical conditions.