  Epitaxial graphene on silicon carbide, or epigraphene, provides an excellent
platform for Hall sensing devices in terms of both high electrical quality and
scalability. However, the challenge in controlling its carrier density has thus
far prevented systematic studies of epigraphene Hall sensor performance. In
this work we investigate epigraphene Hall sensors where epigraphene is doped
across the Dirac point using molecular doping. Depending on the carrier
density, molecular-doped epigraphene Hall sensors reach room temperature
sensitivities $S_V=0.23 V/VT$,$S_I=1440 V/AT$ and magnetic field detection
limits down to $B_{MIN}=27$ $nT/\sqrt{Hz}$ at 20 kHz. Thermally stabilized
devices demonstrate operation up to $T=150$ $^oC$ with $S_V=0.12 V/VT$,
$S_I=300 V/AT$ and $B_{MIN}\approx 100$ $nT/\sqrt{Hz}$ at 20 kHz.
