New chemical vapour deposition reactor at ID10


A prototype chemical vapour deposition reactor allowing operando study of 2D materials on liquid metal catalysts has been developed and commissioned at the ID10 EH1 station, dedicated to investigations of solid and liquid surfaces and interfaces.

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The growth of large-area and high-quality 2D materials is a primary focus of modern surface science and the high-tech industry. Chemical vapour deposition (CVD), relying on the growth at high temperatures and near-atmospheric pressures of highly reactive gases, is a primary method to synthesise these materials. The CVD growth of 2D materials on liquid metal catalysts (LMCats) is a new approach to synthesising extremely high-quality 2D materials. However, the high vapour pressure of LMCats, the near-atmospheric pressure of precursor gases, and elevated temperatures exclude most experimental methods for studying the growth processes in operando.

For this purpose, a prototype LMCat reactor with a portable gas distribution system has been designed and commissioned by an international consortium of scientists in the context of the LMCat FET-Open Horizon 2020 project, and is now available at ID10. The novel reactor allows in-situ and real-time investigations of 2D materials grown on LMCat surfaces at temperatures up to 1600 K and gas pressures up to 2 bar using X-ray (X-ray reflectometry and grazing incidence diffraction) and optical microscopy/spectroscopy methods (Figure 1).



Fig. 1: Schematic of the LMCat reactor showing its (a) outer and (b) inner structures. The components are as follows: 1. Cylindrical X-ray window; 2. Optical probe (here, a Raman probe with integrated video camera); 3. X-Y-Z translation stage of optical probe; 4. Gas lines in/out of reactor; 5. Pressure gauge; 6. Heater control unit with power input and thermocouple reading connections; 7. Water cooling inlet; 8. Gas inlet; 9. Gas outlet; 10. Flow deflectors; 11. The objective lens; 12. Optical window; 13. Heater, and 14. LMCat sample. The blue and green areas in (b) are the optical and X-ray passages between the windows toward the LMCat sample.

The main advantage of the new reactor is the capability to study the growth of 2D materials on liquid metals, which was impossible up to now due to their very high evaporation rate. The innovative, patented gas deflector system [1] significantly limits the deposition of metal vapour at the inner reactor elements, allowing the reactor to be used for months without the need for cleaning. Additionally, the development of radiation-mode optical microscopy and new data treatment methods of X-ray-based measurements [2] allows for real-time growth monitoring, concomitantly from atomic to macro scales. Exemplary investigations of graphene on liquid copper show that the growth can be controlled with unprecedented precision and results in synthesising extremely high-quality and mm-sized 2D crystals of graphene [2].

The new LMCat reactor, together with radiation-mode optical microscopy and new methods for X-ray reflectivity data treatment [3], makes it possible to study operando growth and interactions of 2D materials on liquid metals under very harsh conditions [2]. Thanks to its unique double crystal deflector for the studies of liquid surfaces and the new LMCat reactor, ID10 is currently the only beamline where such studies are possible. The setup, together with a new Raman spectrometer for auxiliary high-temperature experiments, is now available for users.

Principal publication and authors
Development of a reactor for the in situ monitoring of 2D materials growth on liquid metal catalysts, using synchrotron X-ray scattering, Raman spectroscopy, and optical microscopy, M. Saedi (a), J.M. de Voogd (b), A. Sjardin (b), A. Manikas (c), C. Galiotis (c,d), M. Jankowski (e), G. Renaud (e), F. La Porta (f), O. Konovalov (f), G.J.C. van Baarle (b), I.M.N. Groot (a), Rev. Sci. Instrum. 91, 013907 (2020);
(a) Catalysis & Surface Chemistry (CASC), Leiden Institute of Chemistry (LIC), Leiden University (The Netherlands)
(b) Leiden Probe Microscopy (LPM), Leiden (The Netherlands)
(c) Nanotechnology and Advanced Materials Laboratory (NANOTECH), Department of Chemical Engineering, University of Patras (Greece)
(d) Institute of Chemical Engineering Sciences (ICE-HT), Foundations for Research and Technology-Hellas (FORTH), Patras (Greece)
(e) University Grenoble Alpes, CEA, IRIG-DEPHY-MEM, Grenoble (France)
(f) ESRF

[1] Patent PCT/E P2020/058569
[2] M. Jankowski et al., ACS Nano. 15, 9638-9648 (2021).
[3] O.V. Konovalov et al., J. Synchrotron Radiat. 29 (2022).