  We report on the fabrication and characterization of a single-crystal diamond
device for the electrical stimula- tion of light emission from nitrogen-vacancy
(NV0) and other defect-related centers. Pairs of sub-superficial graphitic
micro-electrodes embedded in insulating diamond were fabricated by a 6 MeV C3+
micro-beam irra- diation followed by thermal annealing. A photoluminescence
(PL) characterization evidenced a low radiation damage concentration in the
inter-electrode gap region, which did not significantly affect the PL features
domi- nated by NV centers. The operation of the device in electroluminescence
(EL) regime was investigated by ap- plying a bias voltage at the graphitic
electrodes, resulting in the injection of a high excitation current above a
threshold voltage (~300V), which effectively stimulated an intense EL emission
from NV0 centers. In addition, we report on the new observation of two
additional sharp EL emission lines (at 563 nm and 580 nm) related to
interstitial defects formed during MeV ion beam fabrication.
