Figure 2
From: Fluorescent Fe Embedded Magnetic Nanodiamonds Made by Ion Implantation

Photoluminescence spectra of (a) Original NDs. (b) NDs after Fe implantation (c) Fe-NDs annealed at 800 °C under vacuum. (d) Fe-NDs annealed at 800 °C under vacuum and 450 °C in air.