Low-temperature plasma processing, with its unrivaled ability to deposit or anisotropically etch materials with sub-nanometer control, has been the critical enabler for the success of the U.S. semiconductor industry. Semiconductor manufacturing is entering the “post-silicon era,” characterized by the emergence of alternative “post-silicon” materials that differ dramatically from conventional silicon-based materials. Atomic-layer-thin two-dimensional (2D) materials are particularly promising to replace silicon in nanoscale transistors. This project addresses knowledge gaps in the plasma processing of emerging 2D materials. The central hypothesis of this research is that the defect density in the plasma processing of 2D electronic materials can be minimized or virtually eliminated by tightly controlling the energies and fluxes of plasma species interacting with the 2D materials. To test this hypothesis, the research team will: i) design and construct a plasma system equipped with a uniquely comprehensive array of plasma diagnostics and in-situ surface diagnostic methods that will allow for plasma irradiation of 2D materials with tight control over ion and electron energies and fluxes; ii) study and control defect creation during plasma irradiation of pristine 2D materials; and iii) develop plasma synthesis of defect-free 2D materials through plasma-enhanced atomic layer deposition.