Single-photon emission from Ni-related color centers in CVD diamond

Color centers in diamond are very promising candidates among the possible realizations for practical single-photon sources because of their long-time stable emission at room temperature. The popular nitrogen-vacancy center shows single-photon emission, but within a large, phonon-broadened spectrum (~100nm), which strongly limits its applicability for quantum communication. By contrast, Ni-related centers exhibit narrow emission lines at room temperature. We present investigations on single color centers consisting of Ni and Si created by ion implantation into single crystalline IIa diamond. We use systematic variations of ion doses between 10^8/cm^2 and 10^14/cm^2 and energies between 30keV and 1.8MeV. The Ni-related centers show emission in the near infrared spectral range (~770nm to 787nm) with a small line-width (~3nm FWHM). A measurement of the intensity correlation function proves single-photon emission. Saturation measurements yield a rather high saturation count rate of 77.9 kcounts/s. Polarization dependent measurements indicate the presence of two orthogonal dipoles.Comment: 8 pages, published in conference proceedings of SPIE Photonics Europe 201

Coherence of a charge stabilised tin-vacancy spin in diamond

Quantum information processing (QIP) with solid state spin qubits strongly depends on the efficient initialisation of the qubit’s desired charge state. While the negatively charged tin-vacancy (SnV−) centre in diamond has emerged as an excellent platform for realising QIP protocols due to long spin coherence times at liquid helium temperature and lifetime limited optical transitions, its usefulness is severely limited by termination of the fluorescence under resonant excitation. Here, we unveil the underlying charge cycle, potentially applicable to all group IV-vacancy (G4V) centres, and exploit it to demonstrate highly efficient and rapid initialisation of the desired negative charge state of single SnV centres while preserving long term stable optical resonances. In addition to investigating the optical coherence, we all-optically probe the coherence of the ground state spins by means of coherent population trapping and find a spin dephasing time of 5(1) μs. Furthermore, we demonstrate proof-of-principle single shot spin state readout without the necessity of a magnetic field aligned to the symmetry axis of the defect

A carbene stabilized precursor for the spatial atomic layer deposition of copper thin films

This paper demonstrates a carbene stabilized precursor [Cu(tBuNHC)(hmds)] with suitable volatility, reactivity and thermal stability, that enables the spatial plasma-enhanced atomic layer deposition (APP-ALD) of copper thin films at atmospheric pressure. The resulting conductive and pure copper layers were thoroughly analysed and a comparison of precursor and process with the previously reported silver analogue [Ag(tBuNHC)(hmds)] revealed interesting similarities and notable differences in precursor chemistry and growth characteristics. This first report of APP-ALD grown copper layers is an important starting point for high throughput, low-cost manufacturing of copper films for nano- and optoelectronic devices

Direct liquid injection chemical vapor deposition of ZrO2 films from a heteroleptic Zr precursor: Interplay between film characteristics and corrosion protection of stainless steel

The direct liquid injection chemical vapor deposition (DLI-CVD) of uniform and dense zirconium oxide (ZrO2) thin films applicable as corrosion protection coatings (CPCs) is reported. We present the entire development chain from the rational choice and thermal evaluation of the suitable heteroleptic precursor [Zr(OiPr)2(tbaoac)2] over the detailed DLI-CVD process design and finally benchmarking the CPC behavior using electrochemical impedance spectroscopy (EIS). For a thorough development of the growth process, the deposition temperature (Tdep) is varied in the range of 400 – 700 °C on Si(100) and stainless steel (AISI 304) substrates. Resulting thin films are thoroughly analyzed in terms of structure, composition, and morphology. Grazing incidence X-ray diffractometry (GIXRD) reveals an onset of crystallization at Tdep ≥ 500 °C yielding monoclinic and even cubic phase at low temperatures. At Tdep = 400 °C, isotropic growth of XRD amorphous material is shown to feature cubic crystalline domains at the interfacial region as revealed by electron diffraction. Corrosion results obtained through EIS measurements and further immersion tests revealed improved CPC characteristic for the 400 °C processed ZrO2 coatings compared to the ones deposited at Tdep ≥ 500 °C, yielding valuable insights into the correlation between growth parameter and CPC performance which are of high relevance for future exploration of CPCs

Charge state studies of low energy heavy ions passing through hydrogen and helium gas

Studies of the charge state distribution of low energy (< 1.5 MeV/u), low Z (< 13) heavy ions passing through hydrogen and helium gas of varying target pressure have been performed using separate windowless gas target systems at TRIUMF and the University of Naples. Semi-empirical relationships have been deduced to estimate the equilibrium charge state distributions as a function of beam energy. From these distributions, cross-sections for the relevant charge changing reactions have been deduced. (C) 2002 Elsevier Science B.V. All rights reserved

Aufbau eines Recoil-Massenseparators für die nukleare Astrophysik

Die Planung, der Aufbau und eine experimentelle Bestimmung der Spezifikationen eines Recoil-Separators erfolgten, um einen Detektor zur Verfügung zu haben, mit dessen Hilfe neue Daten zur $^{12}C$$(\alpha,\gamma$)$^{16}O$-Reaktion gewonnen werden können. Der direkte Nachweis der Reaktion über die Detektion der $^{16}O$-Recoil-Kerne stellt hohe Anforderungen an die Akzeptanz und das Herausfiltern des Primärstrahls. Der Separator ist mit ionenoptischen Rechnungen entworfen und nach erfolgtem Aufbau experimentell getestet worden. Die ermittelte Separationsfähigkeit und die mit Hilfe eines Pilotstrahls bestimmte Akzeptanz erlauben $^{12}C$($\alpha,\gamma)$$^{16}O$-Messungen in einem deutlich erweiterten Energiebereich gegenüber bereits existierenden Daten. Durch eine erste Messung dieser Reaktion ist die Funktionstüchtigkeit des Separators und das Zusammenwirken aller Komponenten des Systems gezeigt worden. Darüber hinaus hat er sich in einer weiteren Anwendung als $^{14}C$-Detektor bei Radiocarbondatierungen bewährt

Role of anionic backbone in NHC-stabilized coinage metal complexes: New precursors for atomic layer deposition

Cu and Ag precursors that are volatile, reactive, and thermally stable are currently of high interest for their application in atomic layer deposition (ALD) of thin metal films. In pursuit of new precursors for coinage metals namely Cu and Ag, a series of new N-heterocyclic carbene (NHC) based Cu(I) and Ag(I) complexes were synthesized. Modifications in the substitution pattern of diketonate-based anionic backbones led to five monomeric Cu complexes and four closely related Ag complexes with the general formula [M(tBuNHC)(R)] (M = Cu, Ag; tBuNHC = 1,3-di-tert-butyl-imidazolin-2-ylidene; R = diketonate). Thermal analysis indicated that most of the Cu complexes are thermally stable and volatile compared to the more fragile Ag analogs. One of the promising Cu precursors was evaluated for the ALD of nanoparticulate Cu metal films using hydroquinone as the reducing agent at appreciably low deposition temperatures (145–160 °C). This study highlights the considerable impact of the employed ligand sphere on the structural and thermal properties of metal complexes that are relevant for vapor phase processing of thin films

Role of Anionic Backbone in NHC-Stabilized Coinage Metal Complexes: New Precursors for Atomic Layer Deposition

Funding Information: The authors at RUB thank the German Research Foundation for funding this project (DFG‐DE‐18‐1 and DFG‐DE‐28‐1); the authors at Aalto University acknowledge funding from the Academy of Finland (Profi 3). All the authors also acknowledge funding from the DAAD‐PPP project (57610451) for supporting this work. The authors wish to acknowledge the use of the RawMatTERS Finland Infrastructure (RAMI) at Aalto University. A.P. gratefully acknowledges the PoDoCo funding. Open Access funding enabled and organized by Projekt DEAL. Publisher Copyright: © 2022 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.Cu and Ag precursors that are volatile, reactive, and thermally stable are currently of high interest for their application in atomic-layer deposition (ALD) of thin metal films. In pursuit of new precursors for coinage metals, namely Cu and Ag, a series of new N-heterocyclic carbene (NHC)-based CuI and AgI complexes were synthesized. Modifications in the substitution pattern of diketonate-based anionic backbones led to five monomeric Cu complexes and four closely related Ag complexes with the general formula [M(tBuNHC)(R)] (M=Cu, Ag; tBuNHC=1,3-di-tert-butyl-imidazolin-2-ylidene; R=diketonate). Thermal analysis indicated that most of the Cu complexes are thermally stable and volatile compared to the more fragile Ag analogs. One of the promising Cu precursors was evaluated for the ALD of nanoparticulate Cu metal deposits by using hydroquinone as the reducing agent at appreciably low deposition temperatures (145–160 °C). This study highlights the considerable impact of the employed ligand sphere on the structural and thermal properties of metal complexes that are relevant for vapor-phase processing of thin films.Peer reviewe