Fig. 2: Ultraclean graphene Hall sensors.
From: Magnetic field detection limits for ultraclean graphene Hall sensors
a Optical microscope image of device G1 (w = 1 µm, scale bar: 5 µm). Left cross-section: Hall cross layer structure consisting of monolayer graphene encapsulated with hexagonal boron nitride (hBN) and few-layer graphite. Right cross-section: edge contacts. b Schematic of the measurement configuration, with Hall voltage VH, two-point voltage V2p, bias current I, and out-of-plane magnetic field B. c Top gate voltage (Vg) dependence of the Hall coefficient RH and two-point resistance R2p at 4.2 K under small ac bias and background fields up to B = 100 mT. The upper axis indicates the corresponding electron and hole densities.
