Control of film morphology and its effects on subthreshold characteristics in dibenzotetrathiafulvalene organic thin-film transistors

Abstract

The interface engineering of dibenzotetrathiafulvalene organic thin-film transistors (OTFTs) is reported. Polycrystalline-film morphologies are successfully controlled by surface treatments of silicon dioxide dielectric substrates using hexamethyldisilazane, a silane coupling agent, to tune the average lateral grain sizes between 0.2 and 20μm. The field-effect mobility of the resulting OTFTs is approximately 0.55cm2∕Vs. The effects of the grain sizes on subthreshold properties are discussed in terms of the charge transport against the grain boundaries through the films.