Diamond membrane surface after ion-implantation-induced graphitization for graphite removal: Molecular dynamics simulation

Abstract

Fabrication of diamond membranes, wherein photonic crystals and other nanosized optical devices can be realized, is of great importance. Many spintronic devices are based on specific optically active atomic structures in diamond, such as the nitrogen-vacancy center, and rely on the membrane's performance. One promising approach for realizing such membranes is by creating a heavily damaged layer (rich in broken bonds) in diamond by ion implantation. Following annealing, this layer converts to graphite, which can be chemically removed, leaving a free-standing diamond membrane. Unfortunately, the optical properties of the exposed diamond surface (the diamond-vacuum interface) of such membranes currently are insufficient for high-quality photonic devices. We present molecular dynamics studies of the atomic structure of the etchable graphite/diamond interface. Different implantation and annealing conditions are simulated. The results show that cold implantation, followed by high-temperature annealing ($>1500 {}^{\ifmmode^\circ\else\textdegree\fi{}}\mathrm{C}$) leads to the creation of the sharpest diamond-etchable graphite interface, which should exhibit optimal optical properties among diamond membranes created by the implantation/graphitization method.