A team of researchers across several universities has developed a new, efficient technique for peeling ultra-thin crystalline electronic membranes away from their substrates—an advance that opens the door to wide-ranging industrial-scale applications of the materials. In fact, the team used thin film membranes developed in their experiments to create a record-breaking infrared-detecting sensor that could be used in night vision eyewear or autonomous vehicles.
Led in part by Chang-beom Eom, a professor of materials science and engineering at the University of Wisconsin-Madison, the research appears in the April 22, 2025, issue of the journal Nature.
When it comes to materials science, thin is in. In 2004, researchers discovered graphene, a thin film of carbon just one atom thick. When carbon and a few other special materials are reduced to this two-dimensional arrangement, they take on surprising attributes, including improved strength and electrical conductivity.
Chang-Beom Eom
Eom is an expert in more complex ultrathin materials, crystalline perovskite oxides, containing oxygen and, typically, transition metals in a distinct atomic arrangement. These materials are particularly stable and strong when produced as thin films and can be precisely engineered at the atomic level.
They also offer a huge range of tunable functions, including superconductivity, oxygen catalysis, magnetoresistance, and insulating behaviors. If incorporated into next-generation devices, these films could lead to a whole range of new gadgets, including improved fuel cells, field-effect transistors, spintronic-based memory devices and a wide range of detectors.
Until now, however, it has not been possible to produce membranes of oxide films at an industrial scale. That’s because they are typically grown on a substrate, or base, that helps determine their epitaxial atomic arrangement and properties. Efficiently detaching these delicate thin films from their substrates has proved challenging.
Previously, researchers placed a sacrificial layer between the substrate and the crystalline film. Then they chemically etched away that layer, releasing the crystalline membrane. The process, however, is a balancing act: It’s very slow and can cause the films to crack. As a result, it’s not practical for large crystals or on an industrial scale.
Another technique, placing a layer of graphene between the crystal and substrate to act as an atomic-scale non-stick coating, also faces hurdles and scalability issues.
That’s why Eom and colleagues decided to try a completely different method. Using theoretical techniques and lessons learned from previous experiments, they determined that lead atoms in some complex perovskite oxides can bind up electrons, weakening the atomic bonds between the films and the substrate. They concluded that by incorporating lead into the oxide materials, they could lift or peel the films directly off their substrates without damaging them.
To test the idea, the team grew a lead-containing oxide crystal, PMN-PT, on a common substrate. Indeed, as predicted, the thin film detached perfectly. The analysis showed the crystal was atomically smooth and an exceptionally thin 10 nanometers thick. Because there were no intermediary sacrificial layers to contaminate it, the film was also purer than films produced using other techniques.
Even more, PMN-PT has a practical application; the researchers found their ultra-thin lead-based film has a record-high pyroelectric coefficient, meaning it’s ideal for infrared sensing.
The team then grew multiple batches of the film, affixing 100 squares of the material to a small chip, using each as a heat-sensitive pixel. They found that the sensitivity of the array was on par with current state-of-the art liquid-nitrogen-cooled night-vision devices and could detect an even wider swath of the infrared spectrum. Even more, it worked at room temperature, with no need to cool the sensor to -300 Fahrenheit like the other leading pyroelectric materials.
That means the film could be integrated into portable, lightweight devices for a range of applications, including real-time environmental monitoring or to keep tabs on the heat of semiconductor chips.
Eom says that, besides identifying an exciting new type of ultrathin membrane, the research demonstrates a path for incorporating other complex oxide crystals into real-world devices. The team hopes that this work will help them identify or engineer other oxides with “peel off” properties or to develop a way to incorporate lead atoms into the substrate to keep heavy metals out of finished films.
Chang-Beom Eom is Raymond R. Holton Chair for Engineering and Theodore H. Geballe Professor.
Other UW-Madison authors include Owen Ericksen, Pratap Pal and Shane Lindemann.
Other authors include Xinyuan Zhang, Sangho Lee, Min-Kyu Song, Jun Min Suh, Jung-El Ryu, Ne Myo Han, Haihui Lan, Yanji Shao, Xudong Zheng, and Jeehwan Kim of MIT; Marx Akl and Yunfeng Shi of Rensselaer Polytechnic Institute; Bikram Bhatia of the University of Louisville; Hyunseok Kim of the University of Illinois Urbana-Champaign; Hyun S. Kum of Yonsei University; Celesta Chang of Seoul National University.
The researchers acknowledge support through a Vannevar Bush Faculty Fellowship (ONR N00014-20-1-2844) and the EPiQS Initiative of the Gordon and Betty Moore Foundation (grant no. GBMF9065). Ferroelectric measurement at the University of Wisconsin-Madison was supported by the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences (BES), under award no. DE-FG02-06ER46327.
Featured image caption: The newly developed film could enable lighter, more portable, and highly accurate far-infrared sensing devices, with potential applications for night-vision eyewear and autonomous driving in foggy conditions. Credit: Adam Glanzman.
Portions of this release were originally published by MIT.