Epitaxial growth of trilayer graphene moiré superlattice

【摘要】 The graphene-based moiré superlattice has been demonstrated as an exciting system for investigating strong correlation phenomenon. However, the fabrication of such moiré superlattice mainly relies on transfer technology. Here, we report the epitaxial growth of trilayer graphene(TLG) moiré superlattice on hexagonal boron nitride(h BN) by a remote plasma-enhanced chemical vapor deposition method. The as-grown TLG/h BN shows a uniform moiré pattern with a period of ～ 15 nm by atomic force microscopy(AFM) imaging, which agrees with the lattice mismatch between graphene and h BN. By fabricating the device with both top and bottom gates, we observed a gate-tunable bandgap at charge neutral point(CNP) and displacement field tunable satellite resistance peaks at half and full fillings. The resistance peak at half-filling indicates a strong electron–electron correlation in our grown TLG/h BN superlattice. In addition, we observed quantum Hall states at Landau level filling factors ν = 6, 10, 14,..., indicating that our grown trilayer graphene has the ABC stacking order. Our work suggests that epitaxy provides an easy way to fabricate stable and reproducible two-dimensional strongly correlated electronic materials.更多还原

【Abstract】 The graphene-based moiré superlattice has been demonstrated as an exciting system for investigating strong correlation phenomenon. However, the fabrication of such moiré superlattice mainly relies on transfer technology. Here, we report the epitaxial growth of trilayer graphene(TLG) moiré superlattice on hexagonal boron nitride(h BN) by a remote plasma-enhanced chemical vapor deposition method. The as-grown TLG/h BN shows a uniform moiré pattern with a period of ～ 15 nm by atomic force microscopy(AFM) imaging, which agrees with the lattice mismatch between graphene and h BN. By fabricating the device with both top and bottom gates, we observed a gate-tunable bandgap at charge neutral point(CNP) and displacement field tunable satellite resistance peaks at half and full fillings. The resistance peak at half-filling indicates a strong electron–electron correlation in our grown TLG/h BN superlattice. In addition, we observed quantum Hall states at Landau level filling factors ν = 6, 10, 14,..., indicating that our grown trilayer graphene has the ABC stacking order. Our work suggests that epitaxy provides an easy way to fabricate stable and reproducible two-dimensional strongly correlated electronic materials.更多还原