1. Going beyond copper: wafer-scale synthesis of graphene on sapphire
- Author
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Mishra, N., Forti, S., Fabbri, F., Martini, L., McAleese, C., Conran, B., Whelan, P. R., Shivayogimath, A., Buß, L., Falta, J., Aliaj, I., Roddaro, S., Flege, J. I., Bøggild, P., Teo, K. B. K., and Coletti, C.
- Subjects
Physics - Applied Physics ,Condensed Matter - Materials Science - Abstract
The adoption of graphene in electronics, optoelectronics and photonics is hindered by the difficulty in obtaining high quality material on technologically-relevant substrates, over wafer-scale sizes and with metal contamination levels compatible with industrial requirements. To date, the direct growth of graphene on insulating substrates has proved to be challenging, usually requiring metal-catalysts or yielding defective graphene. In this work, we demonstrate a metal-free approach implemented in commercially available reactors to obtain high-quality monolayer graphene on c-plane sapphire substrates via chemical vapour deposition (CVD). We identify via low energy electron diffraction (LEED), low energy electron microscopy (LEEM) and scanning tunneling microscopy (STM) measurements the Al-rich reconstruction root31R9 of sapphire to be crucial for obtaining epitaxial graphene. Raman spectroscopy and electrical transport measurements reveal high-quality graphene with mobilities consistently above 2000 cm2/Vs. We scale up the process to 4-inch and 6-inch wafer sizes and demonstrate that metal contamination levels are within the limits for back-end-of-line (BEOL) integration. The growth process introduced here establishes a method for the synthesis of wafer-scale graphene films on a technologically viable basis., Comment: 15 main text pages, 4 main text figures, 13 supplementary information pages, 12 supplementary figures, 3 supplementary tables
- Published
- 2019
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