Isotropic contact patterning to improve reproducibility in organic thin-film transistors

A novel approach for improving reproducibility of Organic Field-Effect Transistors electrical performances is proposed. The introduction of isotropic features in the layout of source and drain electrodes is employed to minimize the impact of randomly-distributed crystalline domains in the organic semiconductor film on the reproducibility of basic electrical parameters, such as threshold voltage and charge carrier mobility. A significant reduction of the standard deviation of these parameters is reported over a statistically-relevant set of devices with drop-casted semiconductor, if compared with results obtained in a standard, interdigitated transistor structure. A correlation between electrodes patterning and proposed result is demonstrated by deepening the analysis with the contribution of meniscus-assisted semiconductor printing, in order to precisely control the growth direction of crystals.