# Effect of residual gas composition on epitaxial graphene growth on SiC

## TL;DR

This study investigates how residual gas composition, especially water, affects the quality of epitaxial graphene growth on SiC, emphasizing the benefits of purified argon to minimize defects and optimize growth conditions.

## Contribution

It provides in-situ analysis of residual gases during graphene growth, highlighting the impact of water and the advantages of using purified argon for high-quality graphene production.

## Key findings

- Water reacts with carbon, increasing defects in graphene.
- Purified argon reduces chemical reactions, improving graphene quality.
- Higher temperatures and shorter growth times are preferable.

## Abstract

In recent years, graphene growth optimization has been one of the key routes towards large-scale, high-quality graphene production. We have measured in-situ residual gas content during epitaxial graphene growth on silicon carbide (SiC) to find detrimental factors of epitaxial graphene growth. The growth conditions in high vacuum and purified argon are compared. The grown epitaxial graphene is studied by Raman scattering mapping and mechanical strain, charge density, number of graphene layers and graphene grain size are evaluated. Charge density and carrier mobility has been studied by Hall effect measurements in van der Pauw configuration. We have identified a major role of chemical reaction of carbon and residual water. The rate of the reaction is lowered when purified argon is used. We also show, that according to time varying gas content, it is preferable to grow graphene at higher temperatures and shorter times. Other sources of growth environment contamination are also discussed. The reaction of water and carbon is discussed to be one of the factors increasing number of defects in graphene. The importance of purified argon and its sufficient flow rate is concluded to be important for high-quality graphene growth as it reduces the rate of undesired chemical reactions and provides more stable and defined growth ambient.