Template-Assisted Self Assembly of Fluorescent Nanodiamonds for Scalable Quantum Technologies

Abstract

Milled nanodiamonds containing nitrogen-vacancy (NV) centers provide an excellent platform for sensing applications as they are optically robust, have nanoscale quantum sensitivity, and form colloidal dispersions which enable bottom-up assembly techniques for device integration. However, variations in their size, shape, and surface chemistry limit the ability to position individual nanodiamonds and statistically study properties that affect their optical and quantum characteristics.Here, we present a scalable strategy to form ordered arrays of nanodiamonds using capillary-driven, template-assisted self assembly. This method enables the precise spatial arrangement of isolated nanodiamonds with diameters below 50 nm across millimeter-scale areas. Measurements of over 200 assembled nanodiamonds yield a statistical understanding of their structural, optical, and quantum properties. The NV centers' spin and charge properties are uncorrelated with nanodiamond size, but rather are consistent with heterogeneity in their nanoscale environment. This flexible assembly method, together with improved understanding of the material, will enable the integration of nanodiamonds into future quantum photonic and electronic devices.

Efficient Analysis of Photoluminescence Images for the Classification of Single-Photon Emitters

“…We use two custom-built confocal microscopes to image nanodiamond arrays containing NV centers [58] and exfoliated flakes of h-BN containing SPE. The microscopes feature continuous-wave excitation lasers operating at 532 nm and 592 nm laser, respectively.…”

“…The result is a method that minimizes human input and reduces the time spent in the object detection and second-order autocorrelation stages of SPE exploration. In addition to the array of nanodimonds containing nitrogen-vacancy (NV) centers [58] shown in Figure . 1, we apply the method to characterize SPE in exfoliated flakes of single-crystal h-BN. The two samples are characterized by markedly different SPE properties, in terms of their spatial distribution, brightness, stability, and signal-to-noise ratio, and yet the method succeeds in rapidly classifying emitters in both cases.…”