Researchers from Seoul National University of Science and Technology (SeoulTech) and Kwangwoon University recently used a novel approach called UV-assisted atomic layer deposition (UV-ALD) to treat graphene electrodes. The choice of this technique resulted in the successful production of a high-performance graphene-dielectric interface.
The research team became the first to apply UV-ALD to the deposition of dielectric films onto the surface of graphene. Atomic layer deposition (ALD) involves adding ultra-thin layers at the atomic scale to a substrate, and its significance has grown considerably as semiconductor components have shrunk in size. UV-ALD, which combines ultraviolet light with the deposition process, enables more dielectric film placement than traditional ALD. However, no one had explored the application of UV-ALD for 2D materials such as graphene.
The research team employed UV light with a low energy range (below 10 eV) to deposit atomic layer dielectric films onto the graphene surface, effectively activating the graphene surface without compromising its inherent properties. This activation was achieved under specific conditions (within 5 seconds per cycle during the ALD process), demonstrating the possibility of depositing high-density, high-purity atomic layer dielectric films at low temperatures (below 100℃).
Furthermore, when graphene field effect transistors were fabricated using UV-ALD process, the graphene's exceptional electrical properties remained intact. The outcome was a three-fold increase in charge mobility and a significant reduction in Dirac voltage due to the reduced defects on the graphene surface.
Professor Jihwan An who led the research explained, "Through UV-ALD, we achieved high-performance graphene-dielectric interface." He further added, "Our study resulted in uniform atomic layer deposition without compromising the properties of this 2D material. I hope this development will pave the way for the next-generation semi-conductor and energy devices."