A `Bottom-up´ Redefinition for Mobility and the Effect of Poor Tube-Tube Contact on the Performance of CNT Nanobundle Thin Film Transistors

In this paper, we show that (a) the randomness of mobility of NB-TFT (mu_NB) is not intrinsic, but rather signals the breakdown of ´top-down´ definition mu_NB and a percolation-theory based ´bottom-up´ definition of mu_NB can consistently interpret the results, and (b) the difference between mu_t and mu_NB can be attributed to geometrical parameters of transistor such as tube density, tube length, channel length, etc. and tube-tube contact. Our results not only provide specific guidance to achieve geometry-specific theoretical limits of mu_NB, but also suggest simple characterization of technology-critical tube-tube contact from a few simple measurements.