Phenomenological modeling of charge injection - Beyond the Schottky barrier paradigm

We (re-) investigate the charge injection across a heterojunction of one-dimensional semiconductors by analytical means and by solving self-consistently the effective-mass Schrodinger and the Poisson equation. The charge injection is generally determined by the value of the Schottky barrier. However, we find that a potential step and an effective mass discontinuity across the junction have considerable impact on the charge injection and thus the junction transparency. The impact of the junction transparency on the DC characteristics of a fully gated 50nm carbon nanotube field-effect transistor is demonstrated and device optimization criteria are briefly discussed.