CNR ExploRA

Articolo in rivista, 2015, ENG, 10.1016/j.orgel.2015.03.021

Unified drain-current model of complementary p- and n-type OTFTs

Fabrizio Torricelli, Matteo Ghittorelli, Matteo Rapisarda, Antonio Valletta, Luigi Mariucci, Stephanie Jacob, Romain Coppard, Eugenio Cantatore, Zsolt Miklós Kovács-Vajna, Luigi Colalongo

Department of Information Engineering, University of Brescia, via Branze 38, 25123 Brescia, Italy; CNR-IMM, Via del fosso del Cavaliere 100, Roma, Italy; CEA-LITEN, 17 rue des martyrs, 38054 Grenoble Cedex 9, France; Department of Electrical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands;

A unified drain current model of complementary (p- and n-type) organic thin film transistors (OTFTs) is presented. The model is physically based and takes into account the detailed properties of the organic semiconductor through the density of states (DOS). The drain current depends on the geometrical and physical parameters of the transistor, on the applied gate, drain and source voltages, and on the surface potential at the source and drain contacts. An analytical expression of the surface potential is derived. The proposed model is validated with the numerical calculations and the measurements of both p- and n-type OTFTs fabricated in a printed complementary technology. The provided analyses show that the model is continuous, accurate, and includes the main physical effects taking place in complementary organic transistors. Thanks to its analytical and symmetric formulation, it is suitable for the design of organic integrated circuits. Moreover, the unified physical picture provided by the model enables the extraction of the OTFTs physical parameters, thus it is a very powerful tool for the technology characterization.

Organic electronics (Print) 22 , pp. 5–11