No abstract

Contact effects have been investigated in fully printed p-channel organic thin film transistors with field effect mobility up to 2 cm2/Vs. Electrical characteristics of the organic thin film transistors, with channel length <200lm, are seriously influenced by contact effects with an anomalous increase of the contact resistance for increasing source-drain voltage. Assuming that contact effects are negligible in long channel transistors and using gradual channel approximation, we evaluated the current-voltage characteristics of the injection contact, showing that I-V characteristics can be modeled as a reverse biased Schottky diode, including barrier lowering induced by the Schottky effect

Organic thin-film transistor (OTFT) performance depends on the chemical characteristics of the interface between functional semiconductor/dielectric/conductor materials. Here we report for the first time that OTFT response in top-gate architectures strongly depends on the substrate chemical functionalization. Depending on the nature of the substrate surface, dramatic variations and opposite trends of the TFT threshold voltage (~±50 V) and OFF current (10(5)×!) are observed for both p- and n-channel semiconductors. However, the field-effect mobility varies only marginally (~2×). Our results demonstrate that the substrate is not a mere passive mechanical support.