Optimizing transistor performance of percolating carbon nanotube networks

In percolating networks of mixed metallic and semiconducting carbon nanotubes (CNTs), there is a tradeoff between high on-current (dense networks) and high on/off ratio (sparse networks). Experiments on transistors 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) between 0.04 and 1.29 CNTs/mu m(2) in the on- and off-states (nanotube root mean square length of 5 mu m). Optimized devices with field-effect mobility up to 50 cm(2)/V s at on/off ratio >10(3) were obtained at channel width W=50 mu m and L>70 mu m for p=0.54-0.81 CNTs/mu m(2). (C) 2010 American Institute of Physics. [doi: 10.1063/1.3469930]