Analogue two-dimensional semiconductor electronics
Dmitry K. Polyushkin1, Stefan Wachter1, Lukas Mennel1, Matthias Paur1, Maksym Paliy2, Giuseppe Iannaccone2, Gianluca Fiori2, Daniel Neumaier3,4, Barbara Canto3,4
and Thomas Mueller1
Nat Electron 3, 486–491 (2020)
DOI: 10.1038/s41928-020-0460-6
1Vienna University of Technology, Institute of Photonics, Vienna, Austria.
2Dipartimento di Ingegneria dell’Informazione, Università di Pisa, Pisa, Italy.
3AMO GmbH, Aachen, Germany.
4Bergische Universität Wuppertal, Wuppertal, Germany
Abstract: Digital electronics are ubiquitous in the modern world, but analogue electronics also play a crucial role in many devices and applications. Analogue circuits are typically manufactured using silicon as the active material. However, the desire for improved performance, new devices and flexible integration has—as for their digital counterparts—led to research into alternative materials, including the use of two-dimensional (2D) materials. Here, we show that operational amplifiers—a basic building block of analogue electronics—can be created using the 2D semiconductor molybdenum disulfide (MoS2) as the active material. The device is capable of stable operation with good performance, and we demonstrate its use in feedback circuits including inverting amplifiers, integrators, log amplifiers and transimpedance amplifiers. We also show that our 2D platform can be used to monolithically integrate an analogue signal preconditioning circuit with a MoS2 photodetector.
Fig: a) Schematic of the back-gated transistor architecture;
b) Transfer characteristics of a typical transistor on the chip (W/L = 4);
c) View of a single OPA showing the pinout and transistor labelling
Circuit design and modelling: Because a complete model of back-gated 2D semiconductor FETs is still not readily available, we fitted the experimental results with an Enz–Krummenacher– Vittoz (EKV) model in both, the subthreshold and inversion, regimes. All the transistors operate in the inversion regime, we used the inversion model to simulate the OPA, obtaining a nominal low-frequency Atot gain value.
Acknowledgements: We thank A.J. Molina-Mendoza for technical assistance and N. Schaefer and J.A. Garrido for providing a polyimide substrate. We acknowledge financial support by the European Union (grant agreements 785219 Graphene Flagship, 796388 ECOMAT and 828901 ORIGENAL), the Austrian Science Fund FWF (START Y 539-N16) and the Italian MIUR (FIVE 2D).
