Innovative On‑Chip THz Platform for High‑Sensitivity Thin‑Film Characterization

We are pleased to highlight a recent publication in Nano Letters in which AMO played a significant role. In this work, first author Jimin Lee, together with Alexander Michalski, Simon Sawallich, Max Lemme and Michael Nagel, presents an innovative on‑chip THz‑TDS platform that sets new standards for high‑sensitivity characterization of ultrathin conductive films.

The study, titled “On‑Chip THz‑TDS Platform for High‑Sensitivity Analysis of Graphene and Thin‑Film Conductors”, introduces a compact and reusable THz sensor specifically designed for the analysis of graphene and other weakly conductive thin films. The platform is based on a symmetric coplanar stripline embedded in a low‑permittivity polymer, creating strong electromagnetic confinement and enabling highly efficient coupling to the sample.

Its modular architecture, consisting of a robust motherboard and an interchangeable daughterboard, allows for repeated measurements with different samples. A precisely adjustable air gap ensures controlled and reproducible interaction between the sensor and the material. The results show significantly enhanced absorption signals, including more than 8.8 dB for graphene and more than 21.6 dB for chromium. Clear phase shifts and pulse broadening are also observed, effects that cannot be achieved in free‑space THz systems in the same way.

These findings highlight the potential of the on‑chip THz‑TDS platform as a powerful tool for non‑destructive and highly sensitive characterization of ultrathin conductive films. The approach opens new possibilities for the analysis of graphene and other two‑dimensional materials.

The work was carried out in collaboration with the Chair of Electronic Devices (ELD) at RWTH Aachen University, Protemics GmbH and AMO GmbH.

The project received funding from the German Federal Ministry of Research, Technology and Space within the NEUROTEC project as well as from Zukunftsagentur Rheinisches Revier GmbH.

AMO congratulates Jimin Lee and the entire team on this important publication and their contribution to advancing THz spectroscopy and thin‑film characterization.

📄 Read the paper: https://pubs.acs.org/doi/10.1021/acs.nanolett.5c06544