Ab initio Tribology Study of Silicon Carbide Surfaces

Yun Liu, Izabela Szlufarska, Materials Science Program

Silicon carbide (SiC) is an excellent candidate material for micro-electromechanical systems (MEMS) and nano-electromechanical systems (NEMS) applications because of the superior mechanical and electronic properties of this material. One of the outstanding problems faced with in the design of reliable micro- and nano-devices is undesired friction, which is due to the increased surface-to-volume ratio as the device size is scaled down to the nanometer regime.

Figure 1: Water dissociation on Si-terminated SiC surface (animation from calculation)

Due to the complexity of the energy dissipation mechanisms involved in the sliding process, at this point the atomistic origins of friction are still unclear. This research project is focused on studying the effects of chemistry on the tribological properties of SiC surfaces. We employ first principle calculations, including ab-initio molecular dynamics, to study adhesion, friction, and wear of chemically altered surfaces.

Figure 2: Sample of adhesion computation

Results from this project will yield a fundamental understanding of tribochemistry of SiC in harsh environments and will provide guidance to micro- and nano-fabrication of MEMS and NEMS with highly controlled surface properties.