Two new studies performed at the U.S. Department of Energy’s Argonne National Laboratory have revealed a new pathway for materials scientists to use previously unexplored properties of nanocrystalline-diamond thin films.
The unusually attractive thermal properties of diamond thin films have led scientists to suggest using this material as a heat sink that could be integrated with a number of different semiconducting materials. However, the deposition temperatures for the diamond films typically exceed 800 degrees Celsius—roughly 1500 degrees Fahrenheit, which limits the feasibility of this approach.
By using a new technique that altered the deposition process of the diamond films, nanoscientist Anirudha Sumant and his colleagues at Argonne’s Center for Nanoscale Materials were able to both reduce the temperature to close to 400 degrees Celsius and to tune the thermal properties of the diamond films by controlling their grain size. This permitted the eventual combination of the diamond with two other important materials: graphene and gallium nitride.
In the other study, Sumant used the same technology to combine diamond thin films with gallium nitride, which is used extensively in high-power LEDs. After depositing a 300 nm-thick diamond film on a gallium nitride substrate, Sumant and his colleagues noticed a considerable improvement in the thermal performance.
Both of these studies were carried out in collaboration with Prof. Alexander Balandin at the University of California-Riverside and his graduate students Jie Yu, Guanxiong Liu and Dr. Vivek Goyal, a recent Ph.D. graduate.