Drakopoulou S., Murgia M., Albonetti C., Benaglia S., Borgatti F., Di Lauro M., Bianchi M., Greco P., Papo D., Garcia R., Alessandrini A., Biscarini F.
Advanced Electronic Materials
A growth mode of pentacene thin films deposited by high vacuum sublimation where the morphology versus thickness h “rings” back and forth between rough 3D films with pyramid islands and smooth 2D films with ziqqurat islands is discovered. The roughness s versus h exhibits seamless coherent oscillations whose amplitude and wavelength increase as integer multiples of 1.5 ML thickness. The quantized oscillations are reconducted to dynamic wetting/dewetting transitions involving the upper layers of pentacene film. Importantly, the transconductance of organic field effect transistors, either in solid state or electrolyte-gated, exhibits antiphase oscillations with one-decade swing. Charge mobilities in the wetting regime reach 0.1 cm2 V-1 s-1, in line with high-end values reported for thin-film pentacene transistors. Controlling this growth mode enables the limitations of charge transport imposed by the roughening transition to be overcome, a universal feature of high vacuum growth to date. © 2023 The Authors. Advanced Electronic Materials published by Wiley-VCH GmbH.
