Figure 1
From: Multilayer graphene shows intrinsic resistance peaks in the carrier density dependence
Band structure of tetralayer graphene and sample structure. (a) Simplified band structure in tetralayer graphene. i Tetralayer graphene consists of a set of light-mass and heavy-mass bilayer-like bands, which are offset in energy. ii Perpendicular electric field opens a band gap at the bottoms of the conduction and the valence bands. (b) Optical micrograph of encapsulated tetralayer graphene sample that has a top gate (Top left). The scale bar is 10 μm. Schematic structure of an encapsulated graphene stack is shown in the right panel. G is graphene, BN is h-BN, Si is Si substrate and SiO2 is SiO2 covering on the Si substrate. Tetralayer graphene was encapsulated with thin h-BN flakes, and it was formed on a SiO2/Si substrate. Several layer graphene, which served as a top gate, was deposited onto the top of the encapsulated graphene. Samples were ion-etched into Hall bar shape. Electric contact to the tetralayer graphene was formed by using the technique in ref.15. The lead that is indicated by “Top Gate” in the figure is connected to only the top gate graphene by using the structures illustrated by the two figures at the bottom.
