HOUSTON – (Feb. 26, 2026) – As technology continues to shrink devices to atomic scales, even the slightest imperfection can have significant consequences. Researchers at Rice University have discovered a method to detect elusive defects in a common two-dimensional insulator, potentially enhancing the reliability of future ultrathin electronics.
The study, published in Nano Letters, reveals that these hard-to-detect defects can trap electrical charges, weakening the material and increasing the likelihood of failure at lower voltages. “By showing practical ways to detect when and where these defects form, we help make future devices more reliable and repeatable,” said Hae Yeon Lee, an assistant professor of materials science and nanoengineering at Rice and the study’s corresponding author.
Understanding the Role of Hexagonal Boron Nitride
Ultrathin electronics, including advanced transistors, photodetectors, and quantum devices, are built by stacking sheets of various two-dimensional materials into “heterostructures.” Hexagonal boron nitride (hBN) is a key component in these structures due to its atomic flatness and chemical stability.
“A material’s strength, color, and electrical behaviors come from the way its atoms are arranged,” Lee explained. “However, real materials are not perfect. In hBN, we found that long, narrow misalignments can occur ⎯ similar to the creases that form when a few pages in a book have slipped. These hidden defects form easily and are just as easy to miss.”
Detecting the Invisible
The research team employed a simple yet effective method to uncover these defects. They peeled thin hBN flakes from a bulk crystal using adhesive tape and transferred them onto silicon and silicon dioxide wafers. The researchers suspected that this routine handling might cause defects known as stacking faults.
“To test this, we imaged the same hBN flakes before and after transfer,” Lee said. Under standard optical or atomic force microscopes, the flakes appeared smooth and pristine. However, using cathodoluminescence spectroscopy at Rice’s Shared Equipment Authority, they scanned the material with an electron beam to record the emitted light.
“hBN emits deep ultraviolet light that many labs cannot easily excite,” Lee noted. “This emission map revealed bright, narrow stacking faults that other methods miss ⎯ one reason they have been overlooked.”
Implications for Device Performance
The study found that these faults are more prevalent in thicker flakes, altering the material’s performance. “These hidden defects act like tiny charge pockets and weaken insulation: The same hBN can start leaking electricity at much lower voltage along the defects than nearby areas,” Lee said. This means that two devices built identically could behave differently if one contains these fault lines.
By integrating electron microscopy, cathodoluminescence mapping, and force-based measurements, the team developed a practical approach to identify these defects before they compromise a device. This method is applicable to other layered materials as well.
Funding and Future Research
The research was supported by the U.S. Army Research Office, the Japan Society for the Promotion of Science, the Japan Science and Technology Agency, Japan’s World Premier International Research Center Initiative, and Japan’s MEXT Scholarship. The content in this press release is solely the responsibility of the authors and does not necessarily represent the official views of funding entities.
Looking ahead, the ability to detect and address these defects could play a crucial role in the development of more reliable and efficient ultrathin electronics. As the demand for smaller and more powerful devices grows, understanding and mitigating material imperfections will be vital.
The discovery at Rice University marks a significant step forward in the field of materials science, promising to enhance the performance and durability of next-generation electronic devices.
