Optical microscope image of a substrate with Au central electrode ready for the thermal evaporation of the organic semiconductor.

The great advantage of vertical organic transistors consists in having a much shorter channel lengths and higher switching speeds than planar thin film transistors [1]. In particular, the organic permeable base transistors archi-tecture is very promising to create complementary circuits operating at high frequency in the MHz range [2][3].  Strategies to push the transistor performances in the GHz frequency range have already been presented [4].

In this project, we study the structural and electrical properties of vertical hetero-structures composed of graphene and organic thin films.  We investigate the vertical charge transport and the injection mechanisms at the graphene/semiconductors. Graphene plays the role of a semi-permeable base in the transistors architecture, helping us to improve the control over the electrostatics of the device, and opening pathways for the realization of flexible electronic devices operating at low-voltage and high frequency.

Cross-sections of a C60/Gr/C60 vertical permeable base transistor.

Collaborators in laboratory: Dr. Davide Beretta, Michael Stiefel, Roman Furrer and Prof. Michel Calame

External partners: Dr. Michel Daher Mansour and Prof. Dominique Vuillaume (IEMN, CNRS)

Funding: This project is funded by the Swiss National Science Fondation (SNSF) and the Agence Nationale de la Recherche (ANR).

1. Lüssem, Björn, Alrun Günther, Axel Fischer, Daniel Kasemann, and Karl Leo. “Vertical Organic Tran-sistors.” Journal of Physics: Condensed Matter 27, no. 44 (November 11, 2015): 443003. https://doi.org/10.1088/0953-8984/27/44/443003
2. Huang, Wei, and Antonio Facchetti. “Organic Circuits Reach New Heights.” Nature Electronics, August 3, 2021. https://doi.org/10.1038/s41928-021-00634-5
3. Guo, Erjuan, Shen Xing, Felix Dollinger, René Hübner, Shu-Jen Wang, Zhongbin Wu, Karl Leo, and Hans Kleemann. “Integrated Complementary Inverters and Ring Oscillators Based on Vertical-Channel Dual-Base Organic Thin-Film Transistors.” Nature Electronics, July 15, 2021. https://doi.org/10.1038/s41928-021-00613-w
4. Guo, Erjuan, Felix Dollinger, Baltasar Amaya, Axel Fischer, and Hans Kleemann. “Organic Permeable Base Transistors – Insights and Perspectives.” Advanced Optical Materials, February 22, 2021, 2002058. https://doi.org/10.1002/adom.202002058