Traditionally, engineers use a technique known as atomic layer deposition (ALD) to apply ultra-thin layers of material across a chip’s surface. But the process coats everything, even areas that should stay clean. Think of it like painting an entire house in one step — walls, ceilings and floors — but accidentally covering the windows, too. That’s a problem when working with chips packed with billions of microscopic switches, called transistors, that control the flow of electricity inside smartphones, laptops and other electric devices. To address this challenge, researchers at University of Missouri researchers have developed ultraviolet-enabled atomic layer deposition (UV-ALD). This method uses UV light to precisely control where a thin layer of material — often a metal oxide — is applied during fabrication. The metal oxide coatings help direct the flow of electricity through each transistor, improving the overall efficiency of the chip. Matthias Young, assistant professor at the University of Missouri. Courtesy of the University of Missouri. This targeted approach could reduce manufacturing steps, saving both time and materials. “Our process cuts the traditional four or five manufacturing steps down to just two,” said Matthias Young, an assistant professor at the University of Missouri. “We make the surface ‘sticky’ using UV light and then apply the coating. It only attaches where the light has been applied.” The method could also benefit the environment. “With fewer steps, we reduce the use of harmful chemicals,” Andreas Werbrouck, a postdoctoral researcher and co-author of the study, said. “That’s safer for workers and better for the planet.” In their work, the team demonstrated their approach on a new material, molybdenum disulfide (MoS2), which may help build the next generation of chips. The method dissociates water molecules and produces localized reactive species that bind to the 2D-material surface and act as nucleation sites for ALD. UV light exposure facilitates exposure of large sample areas, and localized patterning using shadow masks controls exposure areas, the researchers said in the study’s abstract. Full functionalization occurs within 90 min of UV and water exposure with the team’s equipment, resulting in dense zinc oxide films. The team also found that the process is transferable to highly ordered pyrolytic graphite, which opens additional material pathways toward 2D nanoelectric devices, the researchers said. The research was published in Chemistry of Materials (www.doi.org/10.1021/acs.chemmater.5c00537).