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We report the incorporation of an ensemble of G centers in silicon-on-insulator (SOI) microrings using ion implantation and conventional nanofabrication. The coupling between the emitters and the resonant modes of the microrings is studied using continuous-wave and time-resolved microphotoluminescence (PL) experiments. We observe the resonant modes of the microrings on PL spectra, on the wide spectral range that is covered by G center emission. By finely tuning the size of the microrings, we match their zero-phonon line at 1278 nm with a resonant mode of quality factor around 3000 and volume 7.2 (λ/n)3. The zero-phonon line intensity is enhanced by a factor of 5, both in continuous-wave and time-resolved measurements. This is attributed to the Purcell enhancement of zero-phonon spontaneous emission into the resonant mode and quantitatively understood considering the distribution of the G center dipoles. Despite the enhancement of the zero-phonon emission, we do not observe any sizeable decrease in the average lifetime of the G centers, which points at a low radiative yield (<10%). We reveal the detrimental impact of parasitic defects in heavily implanted silicon and discuss the perspectives for quantum electrodynamics experiments with individual color centers in lightly implanted SOI rings. Our results provide key information for the development of deterministic single-photon sources for integrated quantum photonics. [ABSTRACT FROM AUTHOR]

Magnesium-and germanium-vacancy centers were produced in diamond by ion implantation and the post-annealing process. Photoluminescence spectroscopy (PL) measurements were performed between 20 and 50 °C. The PL results of the GeV centers are in agreement with those found in the literature, while the MgV center is newly discovered and a not yet broadly investigated color center, but the room temperature PL results are in agreement with the first report. The temperature dependence of the MgV centers above room temperature is unusual: by increasing the temperature, its PL shifts to higher energies, contrary to what is observed for the GeV centers and other known centers in the literature. The zero phonon line width of both centers broadens by increasing the temperature in both investigated centers. The origin of the blue shift observed in the MgV centers as a confinement effect is discarded, because sample is bulk and its origin should lay on the influence of the temperature on the local static structure and the overlapping of the electronic wave functions. Our results show the ability of MgV to be used in future for thermometry. The center is bright and photostable, with a narrow full width at half maximum compared to other centers in diamond and its shift with the temperature is also larger. [ABSTRACT FROM AUTHOR]

Diamond based p-i-n light-emitting diodes, developed to electrically drive single-photon sources in the visible spectral region at room temperature, have the potential to play a key role in quantum based technologies. In order to gain more insight into the charge injection mechanism occurring in these diodes, we carried out an experiment aimed to investigate the electrostatics and the charge carrier transport by the Ion Beam Induced Charge (IBIC) technique, using 1 MeV He microbeam raster scanning of p-i-n structures fabricated in a high purity diamond substrate, using lithographic masking and P and B ion implantation doping. Charge Collection Efficiency (CCE) maps obtained at low ion fluence, show that induced charge pulses arise only from the P-implanted region, whereas no IBIC signals arise from the B-implanted region. This result suggests the formation of a slightly p-type doped substrate, forming a n + -p-p + , rather than the expected p-i-n, structure. However, for high fluence scans of small areas covering the intrinsic gap, CCE maps are more uniform and compatible with a p-i-n structure, suggesting the occurrence of a “priming effect”, which saturates acceptor levels resulting in a decrease of the effective doping of the diamond substrate. [ABSTRACT FROM AUTHOR]

We develop an efficient back gate for silicon-on-insulator (SOI) devices operating at cryogenic temperatures and measure the quadratic hyperfine Stark shift parameter of arsenic donors in isotopically purified 28Si-SOI layers using such structures. The back gate is implemented using MeV ion implantation through the SOI layer forming a metallic electrode in the handle wafer, enabling large and uniform electric fields up to 2V/μm to be applied across the SOI layer. Utilizing this structure, we measure the Stark shift parameters of arsenic donors embedded in the 28Si-SOI layer and find a contact hyperfine Stark parameter of ηa = 1.9±0.7×10-3 μm²/V². We also demonstrate electric-field driven dopant ionization in the SOI device layer, measured by electron spin resonance. [ABSTRACT FROM AUTHOR]

We present nanoscale nuclear magnetic resonance (NMR) measurements performed with nitrogen-vacancy (NV) centers located down to about 2 nm from the diamond surface. NV centers were created by shallow ion implantation followed by a slow, nanometer-by-nanometer removal of diamond material using oxidative etching in air. The close proximity of NV centers to the surface yielded large 1H NMR signals of up to 3.4 μT-rms, corresponding to ~330 statistically polarized or ~10 fully polarized proton spins in a (1.8 nm)3 detection volume. [ABSTRACT FROM AUTHOR]

Quantum information technologies require networks of interacting defect bits. Color centers, especially the nitrogen vacancy (NV–) center in diamond, represent one promising avenue, toward the realisation of such devices. The most successful technique for creating NV– in diamond is ion implantation followed by annealing. Previous experiments have shown that shallow nitrogen implantation (<10 keV) results in NV– centers with a yield of 0.01%–0.1%. We investigate the influence of channeling effects during shallow implantation and statistical diffusion of vacancies using molecular dynamics and Monte Carlo simulation techniques. Energy barriers for the diffusion process were calculated using density functional theory. Our simulations show that 25% of the implanted nitrogens form a NV center, which is in good agreement with our experimental findings. [ABSTRACT FROM AUTHOR]

We present investigations on single Ni/Si related color centers produced via ion implantation into single crystalline type IIa CVD diamond. By testing different ion dose combinations we show that there is an upper limit for both the Ni and the Si dose (10 cm and 10 cm resp.) due to the creation of excess fluorescent background. We demonstrate creation of Ni/Si related centers showing emission in the spectral range between 767 nm and 775 nm and narrow line-widths of ≈2 nm FWHM at room temperature. Measurements of the intensity autocorrelation functions prove single-photon emission. The investigated color centers can be coarsely divided into two groups: Drawing from photon statistics and the degree of polarization in excitation and emission, we find that some color centers behave as two-level, single-dipole systems whereas other centers exhibit three levels and contributions from two orthogonal dipoles. In addition, some color centers feature stable and bright emission with saturation count rates up to 78 kcounts/s whereas others show fluctuating count rates and three-level blinking. [ABSTRACT FROM AUTHOR]

Decreasing structure sizes in both conventional and quantum solid state devices require novel fabrication methods: we present a technology which allows to implant ions through a small hole in the tip of an atomic force microscope. This technique offers a maskless addressing of small structures using different projectiles at kinetic energies between 0.5 and 5.0 keV. Our method aims to implant single atomic ions, molecular ions or charged nanoparticles with nm resolution. We test the method by implanting N+ ions into diamond and generating nitrogen-vacancy color centers. The system is operated with a conventional ion gun. However, in future we will employ an ion trap as a deterministic source of cold single ions. [ABSTRACT FROM AUTHOR]

The authors report a microfabrication procedure of self-actuated piezoresistive scanning probes (SAPSPs). They are designed for a SAPSP instrument that is integrated with an ion beam for aligned single ion implantation in ultrahigh vacuum. The novelty of the design is an integrated hollow pyramid, instead of a previously mechanically hand mounted pyramid [J. Vac. Sci. Technol. B 23, 2798 (2005)]. The pyramid has dual purpose. First it collimates the ion beam and suppresses secondary particles from the back side of the cantilever, so that secondary particles from the target material can be used for single ion detection. Second the pyramid also provides an atomic force microscope tip for the scanning probe. A crucial step in the fabrication is the back side opening via etching for the hollow pyramid. The fabrication procedure will be discussed in detail. [ABSTRACT FROM AUTHOR]

Since a long time, efforts have been made to improve the accuracy of pressure and temperature measurements in diamond anvil cell experiments performed in experimental petrology and high-pressure physics. Here, we report on the state-of-the-art of the research carried out during past few years with the diamond anvils carrying implanted electronic structures (‘intelligent’ anvils, iAnvils). The electronic structures are inserted a few microns below the diamond surface into the diamond lattice by high-energy implantation of boron. These structures can be used as pressure- and temperature-sensitive devices. Another useful application is the fabrication of micro-heaters integrated in the anvils. Pressure- and temperature-induced responses of the sensors (change of resistance) are quantified by low-current measurement equipment. Calibrations against pressure–temperature parameters are performed using well-known phase transitions or by using equation of state of pure substances. Results of in situ measurements performed on iAnvils under pressure and temperature are presented, together with calibration curves for pressure and temperature. Future experiments on in situ measurements of the conductivity dependence of the sensor structures are discussed. [ABSTRACT FROM AUTHOR]

We propose a method for deterministic implantation of single atoms into solids which relies on a linear ion trap as an ion source. Our approach allows a deterministic control of the number of implanted atoms and a spatial resolution of less than 1 nm. Furthermore, the method is expected to work for almost all chemical elements. The deterministic implantation of single phosphor or nitrogen atoms is interesting for the fabrication of scalable solid state quantum computers, in particular for silicon and diamond based schemes. A wide range of further applications is expected for the fabrication of nano and sub-nano electronic devices. [ABSTRACT FROM AUTHOR]

Ion beam synthesis of buried CoSi2 microstructures was performed by high energy ion projection (HEIP) implantation of cobalt into silicon. Ion beam synthesis (mesotaxy) means stoichiometrically high-fluence ion implantation into a heated sample and subsequent annealing of the specimen. The use of the ion projection technique permits an in situ contact mask-free structuring with a sub-micron lateral resolution. The HEIP set-up consists of a superconducting solenoid lens, which projects the structures of a stencil mask onto the target and is driven by a 4 MV tandem accelerator. Because of the high demagnification of the structures the ion current density at the target is increased by two orders of magnitude for small structures.The analysis of the produced structures by optical and electron microscopy, Rutherford backscattering spectroscopy and electrical characterisation shows the good applicability of the Bochum HEIP for IBS. [Copyright &y& Elsevier]

Diamond provides unique technological platform for quantum technologies including quantum computing and communication. Controlled fabrication of optically active defects is a key element for such quantum toolkit. Here we report the production of single color centers emitting in the blue spectral region by high energy implantation of carbon ions. We demonstrate that single implanted defects show sub-poissonian statistics of the emitted photons and can be explored as single photon source in quantum cryptography. Strong zero phonon line at 470.5 nm allows unambiguous identification of this defect as interstitial-related TR12 color center. [ABSTRACT FROM AUTHOR]

Single defect centers in diamond have been generated via nitrogen implantation. The defects have been investigated by single defect center fluorescence microscopy. Optical and electron paramagnetic resonance spectra unambiguously show that the produced defect is the nitrogen-vacancy color center. An analysis of the nitrogen flux together with a determination of the number of nitrogen-vacancy centers yields that on average one 2 MeV nitrogen atom need to be implanted per defect center. [ABSTRACT FROM AUTHOR]

Abstract: The combination of microbeam implantation and in-situ micro RBS/channeling analysis in the Rossendorf nuclear microprobe facility enables crystal damage studies with high current densities not achievable in standard ion implantation experiments. Si(100) samples were implanted with 600keV Si+ ions and a fluence of 1×1016 cm−2. Using a beam spot of 200μm×200μm current densities from 4 to 120μA/cm2 were obtained. The substrate temperature was varied between RT and 265°C. The implanted regions were subsequently analysed by micro RBS/channeling with a 3MeV He+ beam having a spot size of 50μm×50μm. Crystal damage up to amorphisation was observed in dependence on the substrate temperature. Above a critical temperature T C no amorphisation occurs. T C was determined for each series of samples implanted with the same ion current density j. It was found that the empirical Arrhenius relation j ∼exp(−E a/kT C), known from standard implantation experiments, is also valid at high current densities. The observed Arrhenius law can be derived from a model of epitaxial crystallisation stimulated by defect diffusion. [Copyright &y& Elsevier]

We addressed the carrier dynamics in so-called G-centers in silicon (consisting of substitutional-interstitial carbon pairs interacting with interstitial silicons) obtained via ion implantation into a silicon-on-insulator wafer. We performed detailed photoluminescence experiments as a function of excitation energy, incident power, irradiation fluence, and temperature in order to study the impact of radiative and nonradiative recombination channels on the spectrum, yield, and lifetime of G-centers. In the framework of the Huang-Rhys theory with nonperturbative calculations of the acoustic phonon sidebands, we reach an estimation of 1.6 ± 0.1 Å for the spatial extension of the electronic wave function in the G-center. The radiative recombination time measured at low temperature lies in the 6 ns range. The estimation of both radiative and nonradiative recombination rates as a function of temperature further demonstrates a constant radiative lifetime. [ABSTRACT FROM AUTHOR]