When materials are created on a nanometer scale — just a handful of atoms thick — even the thermal energy present at room temperature can cause structural ripples. How these ripples affect the mechanical properties of these thin materials can limit their use in electronics and other key systems.
New research validates theoretical models about how elasticity is scale-dependent — in other words, the elastic properties of a material are not constant, but vary with the size of the piece of material.
Assistant Professor Jian Zhou, PhD ’18, collaborated with researchers from Argonne National Laboratory, Harvard University, Princeton University and Penn State University for a recently published paper in the Proceedings of the National Academy of Sciences.
Using a semiconductor manufacturing process, the team created alumina structures 28 nanometers thick (more than 1,000 times thinner than the diameter of a human hair) on the silicon wafer with thermal-like static ripples, then tested them with lasers to measure their behavior. To remove possible stress to the material that could affect the results, cantilevers held the wafers during testing.
Understanding how thin materials behave is key to electronics and other technology.