  Graphene oxide (GO) flakes have been deposited to bridge the gap between two
epitaxial graphene electrodes to produce all-graphene devices. Electrical
measurements indicate the presence of Schottky barriers (SB) at the
graphene/graphene oxide junctions, as a consequence of the band-gap in GO. The
barrier height is found to be about 0.7 eV, and is reduced after annealing at
180 $^\circ$C, implying that the gap can be tuned by changing the degree of
oxidation. A lower limit of the GO mobility was found to be 850 cm$^2$/Vs,
rivaling silicon. {\it In situ} local oxidation of patterned epitaxial graphene
has been achieved.
