Vertical edge graphite layer on recovered diamond (001) after high-dose ion implantation and high-temperature annealing

A vertical edge graphite layer (VEG) fabricated on a diamond (001) substrate and the recovery of the crystallinity of the diamond substrate following high-dose ion implantation and high-temperature annealing (HTA) was investigated. The Al ions were implanted into the diamond (001) surface at 773 K (500 °C), followed by HTA at 1973 K (1700 °C). The graphite edges were vertically oriented, but each domain was randomly rotated in the in-plane direction, which was confirmed via multiple cross-sectional transmission electron microscopy images obtained from different directions rotated 2, 5, 10, and 15° around the [001] axis. The Raman and photoluminescence exhibited no significant peaks. The initial sp² structure state of the VEG was nucleated in an early stage of the HTA and the surface diamond was subsequently reconstructed, which was confirmed using stopping-and-range-of-ions-in-matter calculations and Rutherford backscattering/channeling (RBS-C) measurements. The RBS-C spectra indicate that the crystal is maintained after hot implantation and is recovered by HTA. This VEG structure may be useful for ohmic contact with diamond electrical devices.