7 research outputs found
Photoluminescence from NVâ centres in 5 nm detonation nanodiamonds: Identification and high sensitivity to magnetic field
This is the final version. Available from the publisher via the DOI in this record.The content of nitrogen-vacancy (NVâ) colour centres in the nanodiamonds (DNDs) produced during the detonation of nitrogen-containing explosives was found to be 1.1â±â0.3âppm. This value is impressive for nanodiamonds of size <â10ânm with intentionally created NVâ centres. The concentration was estimated from the electron paramagnetic resonance as determined from the integrated intensity of the g =â4.27 line. This line is related with âforbiddenâ âmsâ=â2 transitions between the Zeeman levels of a NVâ centreâs ground triplet state. Confocal fluorescence microscopy enables detection of the red photoluminescence (PL) of the NVâ colour centres in nanoscale DND aggregates formed from the 5-nm nanoparticles. Subwavelength emitters consisting of NVâ with sizes a few times smaller than the diffraction-limited spot are clearly distinguished. We have further observed an abrupt drop in the PL intensity when mixing and anti-crossing of the ground and excited states spin levels in NVâ occurs under an applied external magnetic field. This effect is a unique quantum feature of NVâ centres, which cannot be observed for other visible domain light-emitting colour centres in a diamond lattice.Engineering and Physical Sciences Research Council (EPSRC
Nitrogen impurities and fluorescent nitrogen-vacancy centers in detonation nanodiamonds: identification and distinct features
This is the author accepted manuscript. The final version is available from Optical Society of America via the DOI in this recordWe show that nitrogen is the main impurity contained in detonation nanodiamonds at a concentration of 16,000 ppm. The content of nitrogen-vacancy NVâ centers in these nanodiamonds is about 2.7 ppm, which is the largest of all known types of nanodiamonds of size less than 10 nm with artificially created NVâ centers. The removal of graphite-like fragments from the nanodiamond surface allowed us to detect the characteristic photoluminescence of the NVâ color centers in individual nanodiamond aggregates of sizes from 50â100 to 500â700 nm. We have further confirmed the detection of the negatively charged NVâ through the observation of a strong decrease in the photoluminescence intensity when an external magnetic field is applied. Such an effect results from the optically detectable magnetic resonance of the electronic spin triplet ground state of NVâ that cannot be observed in other emitting defects in a similar spectral range, including the neutral NV0 centers