# In situ analysis of catalyst composition during gold catalyzed GaAs nanowire growth

## TL;DR

This study provides real-time measurements of catalyst composition during gold-catalyzed GaAs nanowire growth, revealing how temperature and precursor flux influence catalyst composition and growth mechanisms.

## Contribution

It introduces a novel in situ electron microscopy method to directly measure catalyst composition during nanowire growth, linking phase diagrams to growth behavior.

## Key findings

- Ga content in catalyst increases with temperature and flux
- Phase diagrams help estimate As content in catalyst
- Insights into growth mechanisms from catalyst composition

## Abstract

Semiconductor nanowires offer the opportunity to incorporate novel structures and functionality into electronic and optoelectronic devices. A clear understanding of the nanowire growth mechanism is essential for well-controlled growth of structures with desired properties, but the understanding is currently limited by a lack of empirical measurements of important parameters during growth, such as catalyst particle composition. However, this is difficult to accurately determine by investigating post-growth. We report direct measurement of the catalyst composition of individual gold seeded GaAs nanowires inside an electron microscope as they grow. The Ga content in the catalyst during growth increased with both temperature and Ga precursor flux. A direct comparison of the calculated phase diagrams of the Au-Ga-As ternary system to the measured catalyst composition not only lets us estimate the As content in the catalyst but also indicates the relevance of phase diagrams to understanding nanowire growth.