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.