A Theoretical Study of the Energetic Stability and Geometry of Hydrogen- and Oxygen-Terminated Diamond (100) Surfaces

The energetic stability of diamond (100) surfaces, as a function of degree of hydrogen- and oxygen-related termination, has been studied theoretically using ab initio density functional theory. The results show that an exchange of hydrogen adsorbates with hydroxyl groups is slightly disfavored, whereas a corresponding exchange with oxygen atoms in ketone formations is energetically preferred. The adsorption of oxygen atoms in ether positions are, for surface coverage up to about 50%, largely disfavored compared to a fully H-terminated surface. This oxygen-termination will be energetically improved as the coverage increases above the 50% level. The adsorption energy per terminating species (at 100% surface coverage) is −4.13, −4.30, −5.95, and −6.21 eV for H, OH, O(ketone), and O(ether) species, respectively.