Nitrogen terminated diamond (111) by RF(N2) plasma - chemical states, thermal stability and structural properties

Nitrogen terminated diamond (111) (N-diamond) is suggested to have benefits to near-surface negative nitrogen vacancy (NV-) centers in diamond. To this end, better understanding of defects formation and nitrogen bonding on N-diamond (111) is important. However, there are no studies of N-diamond (111) surface. In this study, we report preparation of N-diamond (111) surface, and evaluation of its thermal stability, chemical states and structural properties. The N-diamond was produced by exposing diamond (111) to radio frequency (RF) nitrogen plasma at two different conditions expected to result in different levels of near surface damage due to the interaction of the activated nitrogen with the diamond surface. X-ray photoelectron spectroscopy (XPS) shows that the amount of incorporated nitrogen on diamond (111) surface differs for these two plasma conditions and is lower than obtained on diamond (100) for the same exposure conditions. Moreover, the thermal stability of nitrogen on non-damaged N-diamond is lower than 700 degrees C as determined by low energy electron diffraction and XPS. The N-diamond (111) surface prepared by non-damaging plasma conditions exhibits a low defects density and well-defined structure, which may pave the way to control the shallow NV- charge state and magnetic spin properties in the near surface region of (111) oriented diamond.