Johanna Huhtasaari, Quantum Device Physics Laboratory

Abstract:

Scalable integration of graphene into (opto)electronics, photonics, and quantum technologies requires large-area single-crystalline films, as grain boundaries degrade mobility and reproducibility. Eliminating grain boundaries and multilayer regions during graphene growth remains challenging. Epitaxial graphene on silicon carbide (SiC) leverages single-crystalline substrates to achieve large-area graphene on SiC, but successful delamination and transfer attempts have so far been challenged by degradation of electronic quality and persistent multilayer graphene patches.

We demonstrate a method to selectively delaminate and transfer the topmost graphene layer from SiC, yielding multilayer-free, large-area graphene single crystals (up to 4″/10 cm in diameter) on standard silicon substrates with preserved electronic quality [1]. Material characterization techniques, including Raman spectroscopy and angle-resolved photoemission spectroscopy (ARPES), confirm the high crystalline quality of the transferred graphene. Quantum transport measurements further demonstrate that the electronic quality of graphene delaminated from SiC is as high as that of flakes exfoliated from graphite. In particular, we observe the half-integer quantum Hall effect — the hallmark of monolayer graphene — in near-centimeter-scale devices, verifying the single-crystallinity of the transferred material.

Our results show that the monolayer-selective delamination is enabled by a specific surface reconstruction of 4H-SiC, reproducible under our growth conditions. Furthermore, we show that graphene can be regrown on the same SiC wafer, greatly reducing the total energy cost of graphene growth. Our results position SiC as a promising platform for scalable and sustainable single-crystalline graphene production for future applications.

1. J. Huhtasaari, et al., Wafer-Scale Single-Crystalline Monolayer Graphene (2025), https://arxiv.org/abs/2512.00394 

Discussion leader: August Yurgens, Professor, Chalmers