  We study the competitive irreversible adsorption of a binary mixture of
monomers and square-shaped particles of linear size $R$ on the square lattice.
With the random sequential adsorption model, we investigate how the jamming
coverage and percolation properties depend on the size ratio $R$ and relative
flux $F$. We find that the onset of percolation of monomers is always lower for
the binary mixture than in the case with only monomers ($R=1$). Moreover, for
values $F$ below a critical value, the higher is the flux or size of the
largest species, the lower is the value of the percolation threshold for
monomers.
