LMCat reactor development

Marc de Voogd, Arthur Sjardin, Gertjan van Baarle

Leiden Probe Microscopy B.V., The Netherlands

Abstract

The most promising method for making high-quality sheets of 2D materials by the ‘bottom-up approach’ is Chemical Vapor Deposition (CVD). In this method, the material for the growth is supplied from the gas phase and a catalytically active substrate enables the separation of the atoms and their reassembly to form a 2D structure.

It is known that formation of defects is prevented by having good control over both the growth conditions and substrate quality. For instance, high-quality graphene can be grown on copper substrates in the molten phase from methane at high temperatures. However, because of the very harsh conditions during synthesis of graphene on liquid copper, only ex situ studies have been reported until now, after the copper has been solidified, possibly affecting the graphene layer that is adhering to it.

We have successfully developed a CVD furnace that allows in situ study of the quality, structure and size of graphene flakes during growth. The substrate heater allows for temperatures exceeding 1500 °C, which enables observations on the CVD growth of graphene on liquid copper. The reactor has a special design, preventing the deposition of copper vapor on the optical and X-ray windows as well as preventing overheating of the windows. The system allows for varying process conditions such as gas composition and substrate temperature while the effects of these variations on the growth of the 2D material are observed. Our live-observation tools include synchrotron X-ray techniques (such as diffraction, reflectometry) and optical techniques (such as microscopy, Raman spectroscopy and reflectometry).

In this talk, we will address the design choices that have been made based on finite element simulations and present the final design of the LMCat Reactor Prototype as it is currently in use by the team. We finalize with our ideas how to further develop the instrument.