CVD growth of ultrapure diamond, generation of NV centers by ion implantation, and their spectroscopic characterization for quantum technological applications

Abstract

Applications of nitrogen-vacancy (NV) centers in diamond in quantum technology have attracted considerable attention in recent years. Deterministic generation of ensembles of NV centers can advance the research on quantum sensing, many-body quantum systems, multipartite entanglement and so on. Here we report the complete process of controlled generation of NV centers in diamond as well as their characterisation: growing diamond films through chemical vapor deposition (CVD), ion implantation and spectroscopic characterization of the defect centers using a confocal microscope. A microwave-assisted CVD set-up is presented which we constructed for the preparation of single-crystalline homoepitaxial diamond films. The films were prepared with minimized nitrogen concentration, which is confirmed through photoluminescence measurements. We demonstrate an in situ ultra high vacuum (UHV) implantation and heating process for creation of NV centers using a novel experimental set-up. For the first time hot implantation has been shown which prevents surface charging effects. We do not observe graphitization due to UHV heating. By optimizing the implantation parameters it has been possible to implant NV centers in a precise way. We present large area mapping of the samples to determine the distribution of the centers and describe the characterization of the centers by spectroscopic techniques. Reducing the decoherence caused by environmental noise is of primary importance for many applications in quantum technology. We demonstrate improvement on coherence time T2 of the NV spins by suppression of their interaction with the surrounding spin-bath using robust dynamical decoupling sequences.

Plasma Treatments and Light Extraction from Fluorinated CVD-Grown (400) Single Crystal Diamond Nanopillars

“…However, this idealized imagination of diamond is not complete, as in reality within the supercell not every carbon atom contains saturated bonds, mostly due to the impurities and crystallographic imperfections incorporated into lattice during the growth [3]. The most common impurity is nitrogen ( 14 N), which is vastly present in synthetic diamond, giving it a remarkable yellow appearance [4]. The nitrogen content among other impurities is the basis for its classification ranging from Type 1b to optical and electronic grade.…”

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

“…Notable solid-state SPE systems include quantum dots [11][12][13] and fluorescent atomic defects within wide band-gap semiconductors such as diamond and silicon carbide [14,15]. More recently, interest has focused on two-dimensional (2D) materials such as hexagonal boron nitride (h-BN) [16][17][18][19][20][21] and transitionmetal dichalcogenides [22][23][24]. There is no known ideal SPE system for all quantum applications, and even those that are suited for particular applications still come with trade-offs in their optical or material properties [25].…”

Optimization of a quantum control sequence for initializing an NV spin register

“…Because of its high Debye temperature (≈ 1800 0 C), the interaction with phonons is weak at RT [17]. In addition, naturally abundant diamond crystals contain magnetic impurities of very low concentration (1.1% 13 C) and growth of ultrapure single crystal diamond contain NVs with slowly dephasing spins [18]. Thus diamond, as a host, ensures that NV centers can be considered as isolated quantum systems, where the long lived electronic and nuclear spins associated with NV can act as a quantum register [19].…”