Does desorption affect the length distributions of nanowires?

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Existing nanowire growth models focus on precursor influx, adatom reflection, and surface diffusion.
• These models predict delayed growth initiation and asymmetric length distributions.
• The effect of material desorption on nanowire length distribution has been largely overlooked.

Purpose of the Study:

• To investigate the impact of material desorption on nanowire length distribution.
• To develop a model incorporating desorption into nanowire growth dynamics.
• To provide insights for optimizing nanowire uniformity in various material systems.

Main Methods:

• Development of a theoretical model that includes the desorption of nanowire material.
• Analysis of the evolution of nanowire length distribution over time.
• Comparison of model predictions with experimental data from self-catalyzed GaAs nanowires.

Main Results:

• Initial nanowire growth exhibits asymmetric length distribution due to slow nucleation.
• At later stages, desorption leads to a symmetric Gaussian length distribution.
• The distribution width increases with higher desorption-to-deposition rates, exceeding Poissonian predictions.

Conclusions:

• Material desorption plays a critical role in determining nanowire length distribution.
• Minimizing desorption is essential for achieving arrays of highly identical nanowires.
• The findings are applicable to a broad range of materials and fabrication processes.