[Research Background and Necessity]

Ultrathin single-crystal oxide membranes have recently garnered significant attention for their potential to overcome the limitations of conventional thin films. Their unique properties make them highly promising for next-generation semiconductors, high-sensitivity sensors, and energy storage devices. These membranes can be detached from their original substrates and transferred onto diverse surfaces, offering unprecedented design flexibility and performance optimization. However, traditional film detachment techniques rely heavily on buffer layers, making them unsuitable for large-scale production due to the added complexity of growing, transferring, and removing these layers.

Meanwhile, there has been growing demand in the field of infrared (IR) sensing for high-performance detectors that can operate at room temperature without the need for bulky and expensive cryogenic cooling systems. Although HgCdTe-based IR sensors remain the commercial standard, their reliance on extreme cooling significantly hampers miniaturization and affordability. Pyroelectric sensors, which do not require cooling, have been proposed as alternatives—but their limited sensitivity has restricted practical use. This study aims to address these technological gaps by developing a novel “Atomic Lift-Off (ALO)” technique that allows atomic-level precision detachment of thin films without buffer layers, enabling record-breaking IR sensing performance at room temperature.

[Key Findings and Impact]

In this study, the researchers theoretically revealed a mechanism by which the presence of lead (Pb) in oxide thin films suppresses interfacial electron transfer and weakens bonding, enabling the first-ever development of the buffer-free "Atomic Lift-Off (ALO)" technique. Using this method, they fabricated highly uniform and large-area (10×10 mm) single-crystal PMN-PT membranes just 10 nm thick. Devices incorporating these membranes achieved a pyroelectric coefficient tens of times higher than conventional counterparts, enabling high-performance IR detection in the far-infrared (Far-IR) range without any cooling.

These results demonstrate the feasibility of next-generation, room-temperature infrared sensors with high sensitivity, paving the way for applications in autonomous vehicles, space exploration, defense, healthcare, and environmental monitoring. The ALO method is also adaptable to a wide range of oxide systems and scalable for mass production, suggesting broad industrial impact in fields such as flexible electronics, advanced semiconductor processes, and energy devices.

[Main Article Body]

Professor Celesta S. Chang of Seoul National University, in collaboration with researchers led by Professor Jeehwan Kim at the Massachusetts Institute of Technology (MIT), has successfully developed a groundbreaking technique to detach ultrathin oxide films for high-performance infrared sensing—without the need for cryogenic cooling systems. The sensor, built on a freestanding oxide membrane only 1/100 the thickness of a human hair, is not only lighter and smaller than conventional models but also far more sensitive.

The study, a joint effort involving top researchers including Professor Jeehwan Kim (MIT), Professor Chang-Beom Eom (University of Wisconsin), and Professor Yunfeng Shi (Rensselaer Polytechnic Institute), was spearheaded by Professor Chang as the corresponding author. She led the theoretical design and core analysis of the work. The team succeeded in eliminating the biggest barrier in IR sensor design—cooling requirements—while dramatically improving sensitivity. Central to their success was the newly developed “Atomic Lift-Off” technique for cleanly detaching single-crystal oxide membranes over large areas (see left image). Unlike previous methods that relied on complex buffer layers and multistep processes, the new approach leveraged the Pb-induced weakening of inter-crystal bonds to achieve precise detachment without buffers.

Using this technique, the team fabricated a 10-nm-thick PMN-PT (lead-based perovskite) membrane that exhibited the highest pyroelectric coefficient ever reported (see right image). Impressively, the sensor can detect long-wavelength infrared (greater than 15 micrometers) at room temperature, outperforming even HgCdTe-based sensors in terms of bandwidth and sensitivity.

“This study opens a new chapter in room-temperature infrared detection,” said Professor Chang. “Unlike conventional sensors that require cooling to achieve high performance, our technology enables broad applications in wearable devices, autonomous driving, space telescopes, and biomedical systems.”

Published online in Nature on April 23 under the title “Atomic Lift-Off of Epitaxial Membranes for Cooling-Free Infrared Detection”, this study was supported by the Ministry of Science and ICT through its Excellent Young Researcher Program.

[Research Paper Details]

Title: Atomic Lift-Off of Epitaxial Membranes for Cooling-Free Infrared Detection
Authors: Xinyuan Zhang, Owen Ericksen, Sangho Lee, Marx Akl, Min-Kyu Song, Haihui Lan, Pratap Pal, Jun Min Suh, Shane Lindemann, Jung-El Ryu, Yanjie Shao, Xudong Zheng, Ne Myo Han, Bikram Bhatia, Hyunseok Kim, Hyun S. Kum, Celesta S. Chang, Yunfeng Shi, Chang-Beom Eom & Jeehwan Kim
Published in: Nature (2025) https://doi.org/10.1038/s41586-025-08874-7

The researchers introduced and demonstrated the ALO technique, which enables buffer-free detachment of oxide films. Utilizing Pb-induced weak covalent bonding at the interface, they achieved high-quality, large-area perovskite membranes with excellent uniformity and crystallinity. The team also provided mechanical criteria for ALO based on the spalling model and showed that cracks propagate with atomic precision under these conditions. With this technology, they achieved the highest pyroelectric coefficient to date and developed a room-temperature FIR detector that outperforms traditional HgCdTe-based devices. This technique is expected to significantly advance both fundamental research and industrial applications of freestanding single-crystal oxides.

[Image Captions]

Left: Ultrathin membrane detached using atomic-level lift-off, Right: Benchmark of pyroelectric coefficient versus film thickness at room temperature, with the present study achieving the highest values ever reported. (Images courtesy of Seoul National University)