  The substrate material of monolayer graphene influences the charge carrier
mobility by various mechanisms. At room temperature, the scattering of
conduction electrons by phonon modes localized at the substrate surface can
severely limit the charge carrier mobility. We here show that for substrates
made of the piezoelectric hexagonal boron nitride (hBN), in comparison to the
widely used SiO$_2$, this mechanism of remote phonon scattering is --at room
temperature-- weaker by almost an order of magnitude, and causes a resistivity
of approximately 3\,$\Omega$. This makes hBN an excellent candidate material
for future graphene based electronic devices operating at room temperature.
