Electrical stimulation of single-photon emission from nitrogen-vacancy centers in diamond with sub-superficial graphitic electrodes

TL;DR

This study demonstrates the electrical excitation of nitrogen-vacancy centers in diamond using sub-surface graphitic electrodes fabricated by focused ion beams, enabling electroluminescence without optical stimulation.

Contribution

It introduces a novel method for electrically stimulating NV centers in diamond via buried graphitic electrodes created with MeV ion beams.

Findings

Significant electroluminescence observed from NV0 centers.

Electrical conduction follows Space Charge Limited Current theory.

Electroluminescence regions correlate with residual vacancy distribution.

Abstract

Focused MeV ion beams with micrometric resolution are suitable tools for the direct writing of conductive graphitic channels buried in an insulating diamond bulk. Their effectiveness has been shown for the fabrication of multi-electrode ionizing radiation detectors and cellular biosensors. In this work we investigate such fabrication method for the electrical excitation of color centers in diamond. Differently from optically-stimulated light emission from color centers in diamond, electroluminescence (EL) requires a high current flowing in the diamond subgap states between the electrodes. With this purpose, buried graphitic electrode pairs with a spacing of 10 $\mu$m were fabricated in the bulk of a single-crystal diamond sample using a 6 MeV C microbeam. The electrical characterization of the structure showed a significant current above an effective voltage threshold of 150V, which was interpreted according to the theory of Space Charge Limited Current. The EL imaging allowed to identify the electroluminescent regions and the residual vacancy distribution associated with the fabrication technique. Measurements evidenced bright electroluminescent emission from native neutrally-charged nitrogen-vacancy centers ($NV^0$); the acquired spectra highlighted the absence of EL associated with radiation damage.