  We study the role of the unknown microphysical properties of carbonaceous
dust particles in determining the amount and size distribution of carbonaceous
dust condensed in type II supernova explosions. We parametrize the
microphysical properties in terms of the shape factor of the grain and the
sticking coefficient of gas-phase carbon atoms onto the grain surfaces. We find
that the amount of dust formed is fairly independent of these properties,
within the parameter range considered, though limited by the available amount
of carbon atoms not locked in CO molecules. However, we find that the
condensation times and size distributions of dust grains depend sensitively on
the microphysical parameters, with the mass distributions being weighted toward
larger effective radii for conditions considering grains with higher sticking
coefficients and/or more aspherical shapes. We discuss that this leads to
important consequences on the predicted extinction law of SN dust and on the
survival rate of the formed grains as they pass through the reverse shock of
the SN. We conclude that a more detailed understanding of the dust formation
process and of the microphysical properties of each dust species needs to be
achieved before robust prediction on the SN dust yields can be performed.
