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In this study, we report originally the excellent electrochemical performance of a micro-supercapacitor based on diamond-coated silicon nanowire (SiNW) electrodes using an aqueous electrolyte (0.1 M LiClO4). The deposition of a nanometric boron-doped diamond coating on SiNWs allowed the enlargement of the electrochemical window up to 3 V maintaining an extraordinary capacitive electrochemical response due to its high overvoltage. Thereby, the device exhibited an areal capacitance of 0.4 mF cm-2, a high power density of 50 mW cm-2 as well as an outstanding cycling stability after 2·106 galvanostatic charge-discharge cycles at a high current density of 10 mA cm-2. In addition, an ultra-fast charge-discharge rate was determined to be 1.5 ms, demonstrating the supercapacitor's enormous ability to deliver high power values at very rapid pulse times (Pmax: 321 mW cm-2). These results also evidence the potential of diamond coating to overcome the main drawbacks of silicon (e.g. rapid silicon oxidation due to presence of water) to be employed in aqueous electrolyte supercapacitors. Consequently, the role of diamond paves the way to high performance SiNW-based micro-supercapacitor development at large electrochemical windows in aqueous electrolytes, which are at present limited to 1 V.

Diamond offers superior material properties for realizing advanced integrated optical components. Particularly attractive is its wide transparency window which covers visible and infrared wavelengths. To take advantage of the potential for broadband waveguiding, diamond needs to be surrounded by broadband transparent cladding materials. Here we use diamond deposited onto aluminum nitride as a platform for integrated optics. We demonstrate essential photonic circuitry for coupling light into on-chip waveguides and show transmission both in the near-infrared and visible wavelength range. Our approach holds promise for functional diamond devices that cover spectral regions up to the mid-infrared. Left: Scanning electron micrograph of a diamond waveguide with an overlay of the mode profile. Right: material stack consisting of polycrystalline diamond (PCD) on aluminum nitride (AlN) on silicon (Si) (not to scale).

Color centers in diamond nanoparticles are promising photoluminescence sources for various applications like bioimaging and labelling. In this work, Silicon Vacancy (SiV) centers were incorporated into individual diamond nanoparticles via controlled background doping during the CVD growth process. The size of the nanoparticles is measured with a scanning electron microscope whereas the SiV centers are characterized by photoluminescence measurements. Due to the low temperature growth conditions applied, the nanoparticles could be removed from the substrate via an annealing step and ultrasonic treatment, creating a suspension of fluorescent diamond nanoparticles.

Silicon nanowires (SiNWs) were successfully coated by uniform, adherent and homogenous ultra-thin crystalline diamond films through microwave enhanced chemical vapor deposition (MWCVD). The as-grown functionalized nanowires were employed as electrodes in a symmetric micro-supercapacitor (MSC) using a protic ionic liquid electrolyte [triethylammonium bis(trifluoromethylsulfonyl)imide; Et3NH TFSI]. The electrochemical performance of the device delivered a specific capacitance of 1.5 mF cm−2 and a power density of 25 mW cm−2 using an enlarged cell voltage of 4 V. Furthermore, a remarkable cycling stability was evaluated after 1 · 106 galvanostatic cycles at a high current density of 10 mA cm−2 with an excellent capacitive behavior. These results confirm that diamond-coated SiNW micro-supercapacitors exhibit very promising performances dealing with MSCs based on CVD-grown SiNWs. Keywords: Supercapacitors, Ionic liquid, Diamond, Silicon nanowires

This work presents novel diamond-based nanostructures formed by a fluorescent nanodiamond core coated with a gold shell (ND@Au). Gold shell was grown on silicon-doped nanodiamonds in water by controlled reduction of gold chloride. The resulting gold-coated nanodiamond samples were characterized by means of scanning electron microscopy, UV–visible, Raman and luminescence spectroscopies. These gold-coated nanodiamonds showed a strong resonance absorption in the visible and near-infrared (NIR) range. When excited with green laser, the silicon doped nanodiamonds emit a stable fluorescence peaked at about 740 nm due to the SiV centers with no photobleaching and photoblinking. In this work we demonstrate that optical properties of the silicon-doped nanodiamonds are retained after the formation of the gold shell.

International audience; A versatile and robust hierarchically multifunctionalized nanostructured material made of poly(3,4-(ethylenedioxy)thiophene) (PEDOT)-coated diamond@silicon nanowires has been demonstrated to be an excellent capacitive electrode for supercapacitor devices. Thus, the electrochemical deposition of nanometric PEDOT films on diamond-coated silicon nanowire (SiNW) electrodes using N-methyl-N-propylpyrrolidinium bis((trifluoromethyl)sulfonyl)imide ionic liquid displayed a specific capacitance value of 140 F g(-1) at a scan rate of 1 mV s(-1). The as-grown functionalized electrodes were evaluated in a symmetric planar microsupercapacitor using butyltrimethylammonium bis((trifluoromethyl)sulfonypimide aprotic ionic liquid as the electrolyte. The device exhibited extraordinary energy and power density values of 26 mJ cm(-2) and 1.3 mW cm(-2) within a large voltage cell of 2.5 V, respectively. In addition, the system was able to retain 80% of its initial capacitance after 15 000 galvanostatic charge-discharge cycles at a high current density of 1 mA cm(-2) while maintaining a Coulombic efficiency around 100%. Therefore, this multifunctionalized hybrid device represents one of the best electrochemical performances concerning coated SiNW electrodes for a high-energy advanced on-chip supercapacitor.

We realize diamond electro-optomechanical resonators operated at frequencies above 100 MHz. The nanomechanical motion is read-out via on-chip diamond photonic circuits showing Q-factors above 1300.

International audience; For a long time sp(2) carbon has been the dominating material for supercapacitor applications. In this paper a new concept of using boron-doped diamond for supercapacitors is proposed. Diamond surface enlargement is realized via bottom-up template-growth. In this method, silicon nanowire electrodes are coated with a thin (similar to 100 nm) layer of nanocrystalline diamond (NCD) by microwave enhanced chemical vapor deposition (MWCVD). The quality of overgrowth is characterized by high resolution scanning electron microscopy which reveals a homogeneous coverage of diamond on Si nanowire surface. To enhance the potential window to 4 V, a room temperature ionic liquid is used as electrolyte. The dilution of the ionic liquid is investigated in terms of conductivity and specific capacitance. The capacitance as measured via cyclic voltammetry reaches 105 mu F/cm(2). An energy density of 84 mu J/cm(2) and a high power density of 0.94 mW/cm(2) are obtained in combination with good stability of over 10,000 charging/discharging cycles. (C) 2014 Elsevier B.V. All rights reserved.

Nanophotonic circuits based on polished diamond thin films are prepared. These circuits cover a wide wavelength range across the entire visible spectrum. Integrated devices are surface functionalized site-specifically and in parallel using dip-pen nanolithography with a minimum linewidth of 100 nm. Multicolor fluorescence is coupled into the underlying photonic network using microring resonators and grating structures., Advanced Optical Materials 2014

The detection of individual photons by superconducting nanowire single-photon detectors is an inherently binary mechanism, revealing either their absence or presence while concealing their spectral information. For multicolor imaging techniques, such as single-photon spectroscopy, fluorescence resonance energy transfer microscopy, and fluorescence correlation spectroscopy, wavelength discrimination is essential and mandates spectral separation prior to detection. Here, we adopt an approach borrowed from quantum photonic integration to realize a compact and scalable waveguide-integrated single-photon spectrometer capable of parallel detection on multiple wavelength channels, with temporal resolution below 50 ps and dark count rates below 10 Hz at 80% of the devices' critical current. We demonstrate multidetector devices for telecommunication and visible wavelengths, and showcase their performance by imaging silicon vacancy color centers in diamond nanoclusters. The fully integrated hybrid superconducting nanophotonic circuits enable simultaneous spectroscopy and lifetime mapping for correlative imaging and provide the ingredients for quantum wavelength-division multiplexing on a chip.

We demonstrate integrated optomechanical circuits with high mechanical quality factors prepared from nanocrystalline diamond thin films. Using chemomechanical polishing, the RMS surface roughness of as grown polycrystalline diamond films is reduced below 3 nm to allow for the fabrication of high-quality nanophotonic circuits. By integrating free-standing nanomechanical resonators into integrated optical devices, efficient read-out of the thermomechanical motion of diamond resonators is achieved with on-chip Mach–Zehnder interferometers. Mechanical quality factors up to 28,800 are measured for four-fold clamped optomechanical resonators coupled to the evanescent near-field of nanophotonic waveguides. Our platform holds promise for large-scale integration of optomechanical circuits for on-chip metrology and sensing applications.

By combining ion beam experiments and atomistic simulations we study the production of defects in graphene on Ir(111) under grazing incidence of low energy Xe ions. We demonstrate that the ions are channeled in between graphene and the substrate, giving rise to chains of vacancy clusters with their edges bending down toward the substrate. These clusters self-organize to a graphene nanomesh via thermally activated diffusion as their formation energy varies within the graphene moiré supercell.

Boron-doped diamond has been applied as an outstanding electrode material for electrochemical applications. Using templated growth techniques, a variety of diamond nanostructures like diamond wires and diamond foams can be fabricated [1, 2]. Using quartz or glass fiber paper as growth templates, porous diamond membranes are fabricated [3]. Compared to polymer membranes or membranes based on sp2 carbons, diamond membranes can survive in aggressive media and high temperature conditions. Also, the ion selectivity can be controlled by surface terminations as well as the bias potential of the membrane. Therefore, this kind of membranes is very promising for the electrochemical separation processes such as desalination, pollutants concentration and protein separation. However, both the fabrication and application of diamond membranes are so far reported only in very limited cases. In this paper, we report our recent progress with respect to the templated diamond growth using quartz fiber paper as the growth template. With optimized microwave CVD growth, nanocrystalline diamond film is fully coated onto the quartz fiber as has been confirmed via SEM. The growth conditions in terms of temperature, methane concentration and boron/carbon ratio are investigated in detail. The diamond quality is evaluated via Raman spectroscopy, and the boron concentration is determined via SIMS. The potential window of the diamond membrane is determined via cyclic voltammetry in an aqueous NaClO4 solution to be ~2.5 V. By applying potential to the membrane, ions will accumulate inside the membrane and change its porosity. As a result, the ion flux through the membrane can be well tuned. This ion selectivity can be used to separate charged molecules. As an example, 5-Carboxyfluorescein and substance P are separated by the diamond membrane under different biases. In a neutral solution, for example, negatively charged 5-caboxyfluorescein can penetrate a positively charged membrane, while the positively charged substance P cannot. Therefore, this membrane can potentially be used for separation processes in biochemical and biomedical applications. Finally, due to the robustness of diamond, the membrane can be cleaned via a high potential (+3 V vs Ag/AgCl) oxidation process in 2 M H2SO4. Metal deposits and organic contaminants are proved to be removable by this method. Therefore, this membrane is also suitable for applications like undersea activities where only simple in-situ maintenances are possible. [1] F. Gao, M.T. Wolfer, C.E. Nebel, Carbon, 80 (2014) 833-840. [2] F. Gao, G. Lewes-Malandrakis, M.T. Wolfer, W. Müller-Sebert, P. Gentile, D. Aradilla, T. Schubert, C.E. Nebel, Diamond Relat. Mater., 51 (2015) 1-6. [3] S. Ruffinatto, H.A. Girard, F. Becher, J.C. Arnault, D. Tromson, P. Bergonzo, Diamond Relat. Mater., 55 (2015) 123-130.

Diamond integrated photonic devices are promising candidates for emerging applications in nanophotonics and quantum optics. Here we demonstrate active modulation of diamond nanophotonic circuits by exploiting mechanical degrees of freedom in free-standing diamond electro-optomechanical resonators. We obtain high quality factors up to 9600, allowing us to read out the driven nanomechanical response with integrated optical interferometers with high sensitivity. We are able to excite higher order mechanical modes up to 115 MHz and observe the nanomechanical response also under ambient conditions., Comment: 15 pages, 4 figures

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