  We show that epitaxial graphene on silicon carbide (epigraphene) grown at
high temperatures (T > 1850 {\deg}C) readily acts as material for implementing
solar-blind ultraviolet (UV) detectors with outstanding performance. We present
centimeter-sized epigraphene metal-semiconductor-metal (MSM) detectors with
peak external quantum efficiency of ~ 85% for wavelengths 250-280 nm,
corresponding to nearly 100% internal quantum efficiency when accounting for
reflection losses. Zero bias operation is possible in asymmetric devices, with
the responsivity to UV remaining as high as R = 134 mA/W, making this a
self-powered detector. The low dark currents Io ~50 fA translate into an
estimated record high specific detectivity D = 3.5 x 10^15 Jones. The
performance that we demonstrate, together with material reproducibility,
renders epigraphene technologically attractive to implement high-performance
planar MSM devices with a low processing effort, including multi-pixel UV
sensor arrays, suitable for a number of practical applications.
