News and Press


New method for surface examination with ultra-thin gold membrane

Knowing the surfaces of materials precisely means being able to assess and improve their properties, behavior and suitability for applications.

Raman spectroscopy is a very frequently used method for the non-destructive analysis of materials. It uses lasers to excite atomic vibrations in the material and optically detect them as a so-called Raman signal. These specific vibrations provide information about material properties such as purity, composition or mechanical stresses. The disadvantage of this method, however, is that the laser light penetrates a few micrometers deep into the material and mainly examines the material volume. As a result, it is often not possible to obtain information about the nature of the surface, as its Raman signal is very weak compared to the material volume and therefore barely measurable. 


Illustration: Scixel

New method uses ultra-thin gold membrane

A research team at Humboldt-Universität zu Berlin led by Sebastian Heeg, in collaboration with Roman Wyss and other researchers from ETH Zurich, the Leibniz Institute for Crystal Growth and Le Mans University, has now developed a new method that amplifies the Raman signal from surfaces by up to 1,000 times, making it measurable. The key to the new method is a wafer-thin gold membrane. This membrane is only 20 nanometers thick and has elongated pores about one hundred nanometers in size. When applied to the surface to be examined, the membrane works in two different ways: firstly, the pores in the membrane concentrate the laser light onto the underlying surface and amplify its Raman signal. Secondly, the membrane prevents the laser from penetrating deeper into the material and thus suppresses the Raman signal from inside the material. The combination of these two effects now enables the investigation of surfaces with previously unknown surface resolution. 

Applications and development opportunities

The new method opens up a whole range of new applications, using existing Raman equipment without upgrading, says Heeg. For example, the Leibniz Institute for Crystal Growth is using the method to investigate a platform for quantum computing consisting of silicon and germanium layers.

Industry has also already expressed interest. The new method could, for example, expand the portfolio of companies in measurement technology and thus make simpler surface characterizations accessible.

In the future, the Raman signal could be significantly amplified using adapted gold membranes. It remains exciting and we will report back.

The scientific journal Nature Communications has published the research teams' paper and can be found here: 
Wyss et al. „Bulk-suppressed and surface-sensitive Raman scattering by transferable plasmonic membranes with irregular slot-shaped nanopores”, 
Nature Communication 15, 5236 (2024) 

Weitere Neuigkeiten

  • Staex wins Deep Tech Award again

    Staex wins Deep Tech Award in the category Web3.0 - DLT, Blockchain, NFT & Metaverse
  • Deutsche Welle report about C1 AG: Climate protection through green methanol

    Deutsche Welle features C1 Green Chemicals AG that has developed new catalysis procedure for affordable, efficient mass production of green methanol.
  • Interview: Founders of nanotechnology startup Mimotype

    We asked the founders about their future plans, co-working as brothers and what advice they give tech-founders.
  • HI:LIGHTS: Detecting heart health through the voice

    AI-based cardiovascular telemonitoring platform "Noah Labs Ark" by startup Noah Labs is already on the market. Voice-based AI software for early detection of heart failure will follow.
  • Transfer BONUS: AI answers calls in medical practices

    HU-Startup relieves over 3,000 medical practices with their product, an AI, which handles incoming calls from patients, processes, and prioritizes them.