  In percolating networks of mixed metallic and semiconducting CNTs, there is a
tradeoff between high on-current (dense networks) and high on/off ratio (sparse
networks in which the metallic CNT fraction is not percolating). Experiments on
devices in a transistor configuration and Monte Carlo simulations were
performed to determine the scaling behavior of device resistivity as a function
of channel length (L) for CNT density p in the range 0.04 - 1.29 CNT/{\mu}m^2
in the on- and off-states. Optimized devices with field-effect mobility up to
50 cm^2/Vs at on/off ratio > 10^3 were obtained at W = 50 {\mu}m, L > 70 {\mu}m
for p = 0.54 - 0.81 CNTs/{\mu}m^2.
