Thermodynamic stability and electronic properties of F- and Cl-terminated diamond

The chemical termination of diamond has important consequences for its electrical and chemical properties. Despite the impressive potential for various scientific and technological applications, halogen termination of diamond is not fully understood. We find using first principle atomistic simulation that 100% fluorinated diamond (100) surface exhibit a chemically stable positive electron affinity of 2.13 eV, whereas 100% chlorination is energetically unfavourable. The positive electron affinity of halogenated diamond generally increases with increasing surface coverage. For mixed halogen and hydrogen termination, a wide range of negative and positive electron affinities can be achieved theoretically by varying the relative concentrations of adsorbed species.