Parameter Space for Chemical Vapor Deposition Graphene in Cold-Wall Reactors under High Precursor Flow Rate

Nowadays, promising proof-of-concept graphene technologies already exist, although converting them into a commercial success requires a high-throughput fabrication process providing a high-quality material. Chemical vapor deposition (CVD) has proven to be the enabling technology for this purpose. However, as typical CVD systems are based on laboratory-scale tubular hot-wall reactors, a comprehensive study is required to translate the optimal thermodynamic configuration into industry-ready CVD cold-wall reactors, capable of increasing the growth area and the process efficiency and yield, hence drastically reducing the costs. In this work, a study on how the thermodynamic parameters affect the growth dynamics and the material quality in a cold-wall reactor under high precursor flow rate is presented. The growth dynamics have been assessed in terms of the lateral growth rate and the nucleation density by means of scanning electron microscopy and image-classification techniques, whereas the quality of the single crystals has been evaluated through Raman mapping and electrical measurements. The parameter space defined by the experimental data has been compared with the predictions based on free Gibbs energy minimization, obtaining an overall good qualitative agreement and proving the suitability of the high precursor flow rate regime for achieving a high-quality material at moderate growth times.