Aachen Graphene & 2D Materials Center
From material science to new device applications
Good news for the community working on two-dimensional materials in Europe: a team of researchers at RWTH Aachen University has successfully implemented the process for growing high-quality hexagonal Boron Nitride at atmospheric pressure and high temperature, increasing the resilience of the supply chain of this unique material.
Scientists from RWTH Aachen, AMO GmbH, Forschungszentrum Julich and the University of Regensburg have shown that in twisted heterobilayers of WSe2 and MoSe2 there is a transfer of valley polarization from excitons in WSe2 to free carriers in MoSe2. This mechanism, which is strongly dependent on the twist angle, may allow the realization of opto-valleytronic devices where the valley polarization is optically excited but extracted and measured by electrical means. The results are reported in npj 2D Materials and Applications.
Researchers at RWTH Aachen University and Forschungszentrum Jülich have uncovered important characteristics of double quantum dots in bilayer graphene, an increasingly promising material for possible applications in quantum technologies. The team has demonstrated near-perfect particle-hole symmetry in graphene quantum dots, which could lead to more efficient quantum information processing. The study has been published in Nature.
Nowadays it is possible to grow high-quality graphene on large scale using chemical vapor deposition (CVD). What remains a major bottleneck for the industrialization of the material is the transfer of graphene from the growth substrate to a target one. A team of researchers from the University of Cambridge and RWTH Aachen University has now developed a methodology for optimizing simultaneously the growth and the transfer process, showing that it is possible to dry-transfer graphene with high-yield, if the crystallographic orientation of the growth surface is chosen appropriately.
Using advanced spectroscopic techniques, researchers from RWTH Aachen University have been able to observe for the first-time domains of tetralayer graphene with ABCB stacking. The results have been reported in ACS Nano.
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.
Continue reading “Healing Achilles heel of two-dimensional transistors”In a compact comment published in Nature Communications, Max Lemme and colleagues outline the most promising fields of applications of two-dimensional (2D) materials, as well as the challenges that still need to be solved to see the appearance of high-tech products enabled by 2D-materials.
Continue reading “2D materials for next generation computing”Shayan Parhizkar and colleagues have demonstrated an integrated infrared-photodetector on a silicon waveguide using two-dimensional platinum diselendide (PtSe2).
Continue reading “A novel infrared photodetector based on two-dimensional platinum diselendide”Following the recent progresses made by the Yazdani group in visualizing broken symmetries and topological states caused by the interaction between electrons in graphene under high magnetic field [1], Markus Morgenstern and Mark Goerbig have released Perspective article in Science [2], where they review in a very accessible language the basic physics beyond the observed effects.
[1] Visualizing broken symmetry and topological defects in a quantum Hall ferromagnet
X. Liu, G. Farahi, C.-L.Chiu, Z. Papic, K. Watanabe, T. Taniguchi, M. P. Zaletel, and A. Yazdani
Science 375, 321 (2021). DOI: 10.1126/science.abm3770
[2] Many-particle electron states in graphene
M. Morgenstern and M. Goerbig
Science 375, 263 (2022). DOI: 10.1126/science.abn2049
Scientists from RWTH Aachen University, AMO GmbH, EPFL and Aixtron SE have demonstrated the first power detectors based on Molybdenum disulphide (MoS2) that operate at zero bias. The fabricated circuits function in Ku-band between 12 and 18GHz, and are the best-performing power detectors fabricated on flexible substrate reported to date. Their dynamic range exceeds 30dB, outperforming other semiconductor technologies, like silicon complementary metal oxide semiconductor (CMOS) circuits and GaAs Schottky diodes.
Continue reading “Progress towards flexible, low-power transceivers based on MoS2”