Lithographic band structure engineering of graphene

Abstract

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Thermoelectric graphene photodetectors with sub-nanosecond response times at terahertz frequencies

“…Following their assembly, we process the heterostructures into antenna-coupled FETs. The GFET channel is first shaped by electron beam lithography (EBL), followed by dry etching of hBN and SLG [39] in SF 6 . The SLG channel geometry is schematically represented in Figure 1: the channel is L C = 3 μm long and W C = 0.8 μm wide.…”

“…By simple geometrical considerations, it can be demonstrated that these extensions increase the perimeter of the stack, i.e., the length of the edge-contacts, thus reducing the contact resistance by 30%, with respect to more standard rectangular channel geometry. Edge Au/Cr electrodes are defined by standard EBL [39,40], followed by metallization (40:5 nm) and lift-off.…”

Superlattices based on van der Waals 2D materials

“…Artificial crystals [128][129][130] Moiré periodicities 131 Bandgap engineering 132,133 (4) Strain-engineered layers. A periodic potential can be produced by subjecting a 2D material flake to periodic tensile/ compressive strains or by introducing a periodic, controlled mismatch between the lattices of two dissimilar 2D materials.…”

“…The small size and the high density of the holes were chosen to manipulate the electronic and magnetic quantum transport behaviour. 132 A third route to engineer the electronic properties of graphene is by applying external electric fields rather than modifying the material itself. A fully encapsulated h-BN/graphene/h-BN heterostructure was transferred onto a 300 nm SiO 2 substrate with an array of periodic nanoholes defined by electron beam lithography.…”

Tunable valley Hall effect in gate-defined graphene superlattices

“…strain, 10,12 substrate effects, [13][14][15] or lithographic etching of a periodic array of holes in the graphene sheet. [16][17][18] Recently, a new approach to band structure engineering has been demonstrated where holes or indentations are made not in the graphene sheet but in an underlying dielectric instead. 19 This procedure avoids introducing any short range disorder to the graphene sheet, and thus limits intervalley scattering while effectively inducing a superlattice potential on the graphene sheet by a gate under the dielectric.…”