  We present transport measurements on quantum dots of sizes 45, 60 and 80 nm
etched with an Ar/O2-plasma into a single graphene sheet, allowing a size
comparison avoiding effects from different graphene flakes. The transport gaps
and addition energies increase with decreasing dot size, as expected, and
display a strong correlation, suggesting the same physical origin for both,
i.e. disorder-induced localization in presence of a small confinement gap. Gate
capacitance measurements indicate that the dot charges are located in the
narrow device region as intended. A dominant role of disorder is further
substantiated by the gate dependence and the magnetic field behavior, allowing
only approximate identification of the electron-hole crossover and spin filling
sequences. Finally, we extract a g-factor consistent with g=2 within the error
bars.
