CNR ExploRA

Articolo in rivista, 2023, ENG, 10.1002/aelm.202300320

Nanoscale Quantized Oscillations in Thin-Film Growth Greatly Enhance Transconductance in Organic Transistors

Drakopoulou, Sofia and Murgia, Mauro and Albonetti, Cristiano and Benaglia, Simone and Borgatti, Francesco and Di Lauro, Michele and Bianchi, Michele and Greco, Pierpaolo and Papo, David and Garcia, Ricardo and Alessandrini, Andrea and Biscarini, Fabio

Dipartimento di Scienze della Vita, Università di Modena e Reggio Emilia, Via Campi 103, Modena 41125, Italy Dipartimento di Fisica Informatica e Matematica, Università di Modena e ReggioEmilia, ViaCampi 213/a, Modena 41125,Italy Center for Translational Neurophysiology, Istituto Italiano di Tecnologia, Via Fossato di Mortara 17-19, Ferrara 44100, Italy CNR-ISMN Institute for the Study of Nanostructured Materials, Via P. Gobetti 101, Bologna I-40129, Italy Instituto de Ciencia de Materiales de Madrid (ICMM) CSIC, Madrid 28049, Spain Sezione di Fisiologia Umana, Università di Ferrara, Via Fossato di Mortara 19, Ferrara 44121, Italy

Abstract 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 ? 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.

Advanced electronic materials 9 (10), pp. 2300320–?