A Comprehensive Study of Transistors Based on Conductive Polymer Matrix Composites

A comprehensive study is conducted on the electron transport in conductive polymer matrix composites (CPMCs), employing the nonequilibrium Green´s function formalism. This paper provides a microscopic insight into the electron tunneling through the potential barriers existing between conducting sites. It is shown that Wentzel-Kramers-Brillouin approximation as well as other models with simple barrier shapes, which are widely used in literature, can lead to inaccurate results in comparison with the quantum mechanical approach using a hyperbolic barrier. In this paper, unlike most previous ones, percolation-related effects are disregarded for further focus on electron transport through the polymer potential barriers. It is assumed that a tunneling-conductive channel exists between the electrodes. This can be created either by applying electric field alignment or using a filler volume fraction higher than the percolation threshold. A two electrode resistive device is studied and the results indicate that a conductor-insulator transition occurs at a barrier thickness of ~1.7 nm and the barrier thickness should be larger than several angstroms. Next, a novel tunneling field-effect structure based on CPMCs is introduced and its characteristics are comprehensively investigated. This device features a remarkably simple structure, an extremely high channel to gate coupling, a large transconductance, and a high current level. Besides, it has the advantage of being based on polymers. This ensures favorable physical properties, ease of fabrication, and low-cost processing techniques.