When designing super-small electronics, engineers have long focused on picking the right materials. But researchers at the National University of Singapore have discovered something surprising: sometimes the tiny empty spaces between parts matter more than the material itself.
The team, working from the College of Design and Engineering, found that minuscule gaps between electrodes can cause more unwanted electrical leakage than the choice of atom-thin material. Their discovery, published in Nature Materials on July 1, 2026, could change how future computer chips and memory devices are built.
"At this extremely small scale, we've shown that tiny physical gaps between electrodes can matter more than the material's own ability to block electrical current," said Associate Professor Mario Lanza, who led the study.
To understand why this matters, imagine building a wall to keep water from leaking. Engineers have focused on choosing the best building material. But Lanza's team found that even the best material won't work well if the wall doesn't sit flat against its foundation. Tiny gaps change how easily electricity slips through — a phenomenon called quantum tunneling, where electrons pass through barriers that should stop them.
The researchers tested several atomically thin materials, including hexagonal boron nitride, molybdenum disulfide, and tungsten disulfide. They expected the strongest insulator to block current best. Instead, they found that hexagonal boron nitride in its thinnest form actually let more current through than materials with weaker insulating properties.
The reason? Thickness. A thinner material gives electrons a shorter distance to cross, making leakage more likely.
"One of the surprising lessons from this work is that conventional expectations about insulating materials can change at the atomic scale," said Dr. Yue Yuan, the study's first author. "When the material is less than one nanometer thick, even a very small change in physical distance can have a major effect on how easily electrons pass through."
The team combined advanced measurements, device testing, and computer modeling to compare devices with smooth graphite electrodes against rougher metal electrodes like gold and ruthenium. The rougher surfaces created gaps that altered how electricity behaved.
This discovery helps explain why scientists studying similar atom-thin materials sometimes got very different results. Devices that looked identical on the surface may have had invisible gaps at their interfaces, producing different electrical behavior.
The findings could guide development of future electronics that are smaller, thinner, and more energy-efficient — including the advanced computer chips and ultra-thin memory devices that power our phones, laptops, and data centers. Instead of focusing only on material properties, engineers will need to consider the whole device structure: electrode smoothness, interface quality, and the true distance electrons must travel.
"This study provides a foundation for designing more reliable atomically thin electronic devices by improving interface uniformity, engineering smoother electrodes and minimizing nanoscale gaps and contaminants," Lanza said.