Electrical Engineering and Information Technology

On this page we present current contributions to research in electrical engineering and information technology

Portrait of Prof. Lemme (© JRF)

Healing Achilles heel of two-dimensional transistors

Stability – in the sense of stable operation thorough lifetime – is one of the key characteristics that an electronic device need to present to be suitable for applications. And it is the Achilles heel of transistors based on two-dimensional materials, which typically show much worse stability than devices based on silicon. A team of researchers from TU Wien, AMO GmbH, RWTH Aachen University and Wuppertal University has now demonstrated a novel engineering approach to enhance the electrical stability of two-dimensional transistors by carefully tuning the Fermi energy. The results have been reported in Nature Electronics.

Today, there is little doubt that devices based on graphene and other two-dimensional (2D) materials can exceed the state of the art for certain applications, thanks to their intrinsic properties. Two-dimensional materials are also seen as some of the most promising candidates for realizing ultimately scaled transistors at the end of the roadmap of silicon technology.  However, devices based on 2D materials often show poor electrical stability, meaning that their behavior changes depending on their operation history.

“Component reliability is one aspect that is often neglected in research. This is precisely where we have been working for several years, because it is of central importance for applications.” explains Professor Max Lemme, scientific director of AMO GmbH and Head of the Chair of Electronic Devices at RWTH. The instability is not only caused by 2D materials themselves, but mostly by charges trapped into the oxide-insulator used to fabricate the transistors. “Ideally, one would like to use a different insulator with fewer charge traps,” says Lemme, “but there are no scalable solutions for this yet. In our work, we have shown instead that it is possible to use a standard insulator such as aluminum oxide and to significantly suppress the adverse effects of the charge traps in the oxide, by adjusting the charge carrier density in the 2D material.”

© Martin Braun

The work combines a thorough theoretical analysis of the novel approach – dubbed by the authors ‘stability-based design’ – and a proof of principle demonstration of the concept, performed by measuring different types of graphene-based FETs. The key idea of the approach is to try to engineer the combination 2D-material/insulator in such a way that the energy of the charge traps in the insulator is as different as possible from the one of the charge carriers in the 2D material. Lemme explains: “Graphene based FETs were the ideal test bed for our approach, as it is relatively easy to tune the energy of charge carriers in graphene. The approach, however, is applicable to all FETs based on 2D semiconductors”.  These results represent a major step forward towards stable and reliable 2D materials transistors to be integrated in semiconductor technology.

Bibliographic information:
T. Knobloch, B. Uzlu, Y. Yu. I.llarionov, Z. Wang, M. Otto, L. Filipovic, M. Waltl, D. Neumaier, M. C. Lemme, T. Grasser, Improving stability in two-dimensional transistors with amorphous gate oxides by Fermi-level tuning, Nature Electronics (2022) – Open Access
DOI: 10.1038/s41928-022-00768-0

Contact:
Prof. Max C. Lemme
AMO GmbH
lemme@amo.de

From October 30, 2021 to February 13, 2022, the 150th anniversary exhibition of the RWTH took place at the Centre de Charlemagne in Aachen. ISEA – the Institute for Power Electronics and Electrical Drives – also contributed with some exhibits to illustrate the highlights from research and the development of RWTH since its foundation in October 1870.
For all those who could not be there and see this wonderful exhibition for themselves, we have a short review.

Among others, the IKS was also involved. The project “Virtual visit” dealt with the 3D telephony of the future: Who hasn’t had the wish to beam to the other side while talking on the phone?  At least via audio, this would be possible in the future; for example, one could already sit virtually in the middle of a concert of the Aachen Symphony Orchestra.
Prof. Dr. Peter Jax presented the state of the art as well as current research topics in his lecture and invited to an exciting discussion afterwards.
It was very interesting to get to know a current research project of the IKS and to experience the research live.

The content of the lecture was further illustrated in the exhibition by virtually sitting in the middle of the concert of the Aachen Symphony Orchestra. The aim was to perceive the sound in 3 dimensions. To experience this phenomenon, all one had to do was put on a pair of virtual reality glasses and enjoy the sounds of the Aachen Symphony Orchestra.

It was particularly fascinating to be able to hear the sounds from all directions and at the same time to be able to identify the direction from which they came. It was easy to follow the sounds more closely by turning around to look at them with the glasses. It was really a great insight into the research of the IKS.

Professor Dr. Haris Gačanin, head of the Chair for Distributed Signal Processing and co-director of the Institute of Communication Technologies and Embedded Systems, presented the research activities of the 6GEM Research Hub at the Thinknet 6G Summit. The Thinknet 6G Summit is an international conference focused on the next generation of communication networks.
As digitalization progresses, mobile communications communication takes on the crucial role of providing the communication infrastructure for society as a whole. The current generation of mobile communication, 5G, is the first to shift focus away from individual end-user communications to industrial applications (Industry 4.0), logistics, transportation and eHealth. The subsequent generation, 6G, is expected to further expand network capacity and speed to enable applications with significantly higher connectivity requirements, such as fully autonomous driving.
In this regard, the 6GEM Research Hub is focusing more on the practical impact that 6G will have on our society. After all, this advanced infrastructure must provide adaptive and resilient communication systemss for a wide range of requirements and applications for the benefit of humanity.

The Institute of Hearing Technology and Acoustics is proud to announce that Professor Michael Vorländer has recently been awarded the prestigious Rayleigh Medal, the highest award of the Institute of Acoustics. Therefore, we from the Faculty of Electrical Engineering and Information Technology also say, congratulations!

The Rayleigh Medal is the highest award of the Institute of Acoustics and is given without regard to age to individuals who have made outstanding contributions to acoustics. The medal is named for John William Strutt, Third Baron Rayleigh (1842-1919), a highly versatile physicist who conducted both experimental and theoretical research in virtually all areas of the field. His book The Theory of Sound remains a landmark in the development of acoustics.

With this award, Michael joins a list of very well-known acousticians such as Manfred Schröder, Hugo Fastl, Leo Beranek, and his predecessor Heinrich Kuttruff who have also been awarded this medal.

The Faculty of Electrical Engineering and Information Technology warmly congratulates students Daniyar Kizatov, Jiayi He, Anshul Prashar and Shunjiro Sodei and all involved on their successful second place in the international Biosensor Competition SensUs! The fourth generation of the RWTH Aachen student team AixSense participated in the SensUs competition at Eindhoven University of Technology this year.

Consisting of four ambitious students from the fields of Computer Engineering and Micro-Nano-Electronics, the interdisciplinary team has spent the past six months developing a prototype biosensor to detect the influenza A virus. Thus, the team worked in the laboratories and clean rooms of our Institute of Materials in Electrical Engineering 1 at RWTH, where the chips (see picture on the right) were produced as key components for the technology. The team was supervised by Prof. Sven Ingebrandt and Dr. Vivek Pachauri.

Daniyar Kizatov, Jiayi He, Anshul Prashar, Shunjiro Sodei | Copyright: IWE1

At the final event, the AixSense team presented the biosensor prototype and was awarded in four categories for analytical performance, creativity, transferability of the concept and public inspiration. In the Analytical Performance category, RWTH Aachen University took second place by a slight margin.

 “Our team was never so close to winning one of the most important awards. It was very close and we are proud of our performance.”

– Daniyar Kizatov, team leader of AixSense

This year, 14 student teams from Denmark, Egypt, the Netherlands, Germany, Portugal, Switzerland, China, Sweden, the USA, Belgium, the UK, Canada and Spain took part in the competition.

The biosensor has been known to the public at the latest since the introduction of the Covid rapid test – but the SensUs community has been supporting young scientists to present their research in the field of biosensors internationally for five years. Every year, a new generation of teams faces the challenge of developing a biosensor prototype for a new disease. So far, the focus has been on detecting biomarkers for kidney failure, heart failure, antibiotic resistance, rheumatism and epilepsy.

Next year, the SensUs competition aims to detect cytokines as crucial proteins in the immune system. The application phase for the next generation of the AixSense team starts in December 2021 – more information on how to apply can be found here.

(Original article press release IWE1)

Sorry, this entry is only available in German.

The Henriette Herz Scouting Program, funded by the BMBF, aims to expand and diversify the Alexander von Humboldt Foundation’s network. The program specifically recruits established and experienced researchers who already have an international network. It enables the scouts to select up to three scientists who will then directly receive a fellowship. The first will go to a female researcher.
The scouts aim to approach international researchers from abroad who have not yet been considered for an academic fellowship to the Humboldt Foundation and a research stay in Germany. As a result, the program will attract new collaborative partners for Germany, both from a specialist and geographical perspective. At the same time, the aim is to increase the quota of women sponsored in the Humboldt Research Fellowship Programme.

We are very pleased that Prof. Antonello Monti has been selected for the Henriette Herz Scouting Program.

“The program offers us the possibility to increase our international cooperation by creating new links with universities that are not currently working with us.
What is extremely interesting about this program is the possibility to be really fast in offering the scholarship. By skipping the standard review process, the time between identification of candidates to the start of the scholarship becomes extremely short.” – Prof. Monti

 The Henriette Herz Scouting Program, funded by the BMBF, aims to expand and diversify the Alexander von Humboldt Foundation’s network. The program specifically recruits established and experienced researchers who already have an international network. It enables the scouts to select up to three scientists who will then directly receive a fellowship. The first will go to a female researcher.
The scouts aim to approach international researchers from abroad who have not yet been considered for an academic fellowship to the Humboldt Foundation and a research stay in Germany. As a result, the program will attract new collaborative partners for Germany, both from a specialist and geographical perspective. At the same time, the aim is to increase the quota of women sponsored in the Humboldt Research Fellowship Programme.

We are very pleased that Prof. Antonello Monti has been selected for the Henriette Herz Scouting Program.

“The program offers us the possibility to increase our international cooperation by creating new links with universities that are not currently working with us.
What is extremely interesting about this program is the possibility to be really fast in offering the scholarship. By skipping the standard review process, the time between identification of candidates to the start of the scholarship becomes extremely short.” – Prof. Monti

The Henriette Herz Scouting Program, funded by the BMBF, aims to expand and diversify the Alexander von Humboldt Foundation’s network. The program specifically recruits established and experienced researchers who already have an international network. It enables the scouts to select up to three scientists who will then directly receive a fellowship. The first will go to a female researcher.
The scouts aim to approach international researchers from abroad who have not yet been considered for an academic fellowship to the Humboldt Foundation and a research stay in Germany. As a result, the program will attract new collaborative partners for Germany, both from a specialist and geographical perspective. At the same time, the aim is to increase the quota of women sponsored in the Humboldt Research Fellowship Programme.

We are very pleased that Prof. Antonello Monti has been selected for the Henriette Herz Scouting Program.

“The program offers us the possibility to increase our international cooperation by creating new links with universities that are not currently working with us.
What is extremely interesting about this program is the possibility to be really fast in offering the scholarship. By skipping the standard review process, the time between identification of candidates to the start of the scholarship becomes extremely short.” – Prof. Monti

The Henriette Herz Scouting Program, funded by the BMBF, aims to expand and diversify the Alexander von Humboldt Foundation’s network. The program specifically recruits established and experienced researchers who already have an international network. It enables the scouts to select up to three scientists who will then directly receive a fellowship. The first will go to a female researcher.
The scouts aim to approach international researchers from abroad who have not yet been considered for an academic fellowship to the Humboldt Foundation and a research stay in Germany. As a result, the program will attract new collaborative partners for Germany, both from a specialist and geographical perspective. At the same time, the aim is to increase the quota of women sponsored in the Humboldt Research Fellowship Programme.

We are very pleased that Prof. Antonello Monti has been selected for the Henriette Herz Scouting Program.

Sorry, this entry is only available in German.