Fig. 1: Performance of micrometer-scale Hall sensors.

Minimum magnetic field detection limit S_B^1/2 at 1 kHz vs. the width w of Hall sensors reported here and in the literature. The black markers show the best performance of our graphite-gated (circles; G1–G3) and metal-gated (diamonds; M1 and M2) devices in zero background magnetic field, and the red circles show the performance of G1 in 1 T and 3 T background field as indicated. All other markers are estimates of the best performance in zero background field of devices made from semiconductor- and graphene-based structures, including graphene grown by chemical vapor deposition (“G”), epitaxial graphene (“G/SiC”), and hBN-encapsulated exfoliated graphene (“hBN”). Filled (open) markers correspond to measurements at 4.2 K (300 K). Solid lines are a guide to the eye connecting markers corresponding to the same material and fabrication process. Dashed lines mark constant S_B^1/2w. Markers with error bars are extrapolated from measurements reported at different frequencies, assuming the noise is dominated by 1/f noise and scales as f^−α (error bars mark the range 0.4 < α < 0.6).