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. 
 

Verfahren

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

  • Job Insert: Director of the Chemical Invention Factory (m/w/d)

    At TU, the Chemical Invention Factory is currently being established, a new laboratory and startup hub for projects in the field of chemistry. The university is now looking to fill the leadership position. Apply now!
  • Job Insert: Event Manager (m/w/d)

    The Innovation Management team is growing! We’re looking for an Event Manager (m/f/d) for the third-party funded project “T!Raum GreenChem.” Apply now!
  • The Humboldt Founders Report 2025 for Q2 has just been released

    We’ve got the latest figures from the Humboldt Founders Report and they’re impressive! Every category saw growth in the second quarter of the year.
  • Over 20 million euros in initial funding for UNITE from economic and federal sources

    The start-up incubator UNITE was recognized as one of ten projects nationwide in the EXIST flagship competition and is receiving 10 million euros. An additional 10 million euros comes from private capital.
  • Noah Labs in the Fast Lane

    Deep Tech Award in the "Artificial Intelligence" category goes to health-tech startup Noah Labs.