Photoelectrodeposition of copper on boron-doped diamond films (BDD) was investigated. In this work, two different doped films were analyzed. Copper particles were deposited in the potentiostat mode and under UV irradiation. The BDD film as-grown and the BDD film modifed with Cu (Cu/BDD) on the surface were characterized by Raman Spectroscopy and Scanning Electron Microscopy (SEM) respectivily. These electrodes were tested as electrocatalysts for nitrate reduction in Britton-Robinson buffer solution (pH=3). Electrochemical measurements showed that the electrode with high doping level displayed the best electrocatalytic activity.

In this paper, the influence of the doping level at boron doped nanocrystalline diamond (BDND) films in the electrochemical determination of nitrite was reported. The morphology and the structure modifications as function of the boron doping level increase were observed. Two different doping levels were considered. A BDND film with a doping level of 30.000 ppm and one another with a doping level of 10.000 ppm was used. The columnar growth for the 30.000 ppm BDND led to a higher surface roughness and also to a greater grain size when compared to that 10.000 ppm BDND. The Raman spectra shown higher sp2-bonded carbon amount in grain boundary for the 10.000 ppm BDND film due to decrease of the grain size. The morphological and structural modifications of the BDND films were crucial for nitrite oxidation process. The 30.000 ppm BDND electrode presented a better sensitivity to the nitrite oxidation and a lower detection limit (DL) on the “as-grown” condition, while the 10.000 ppm BDND electrode presented a better analytical sensitivity and a lower DL after the surface pre-treatment with hydrogen plasma.

Boron-doped nanocrystalline diamond (BDND) films were grown on silicon substrates by hot filament chemical vapor deposition in Ar/H2/CH4 gas mixtures. The boron source was obtained from an additional H2 line passing through a bubbler containing B2O3 dissolved in methanol with different B/C ratios. The transition from ultrananocrystalline to nanocrystalline diamond films is clearly shown by the addition of boron dopant to the growth gas mixture. The morphology and structure of these films have markedly different properties. The top view and the cross section of the films were characterized by scanning electron microscopy showing the transition from ultrananocrystalline growth (renucleation process) to a columnar structure of NCD films. Finally, the grain size was obtained from X-ray diffraction patterns of the films. The diamond average grain size increased from 10 to 35 nm for films with 2000 and 30,000 ppm B/C, respectively.

Boron doped ultrananocrystalline diamond (UNCD)/hydrogenated amorphous carbon composite films prepared by pulsed laser deposition were structurally investigated. With an increase in the boron content, the grain size was increased from 5 to 23 nm accompanying by the lattice constant approaching to that of bulk diamond. The near-edge X-ray absorption fine-structure revealed that boron atoms are preferentially distributed into grain boundaries. On the basis of the results, the roles of the boron atoms in the enhanced crystalline growth are discussed. We consider that the crystalline growth posterior to the nucleation is facilitated by boron atoms existing neighbor to UNCD grains or by boron-containing energetic species in plasma.

We have proposed the use of glass-like carbon (GC), as mold material because the 27-maximum etching selectivity of polysiloxane film against GC, which was approximately sixtimes larger than that of polysiloxane film against chemical vapor deposited (CVD) diamond film. We have investigated the fabrication of diamond nanopit arrays by room-temperature curing nanoimprint lithography (RTC-NIL) using GC mold, as applications to the emitter and the micro-gear. The polysiloxane has in the state of sticky liquid at room-temperature and negative-exposure characteristic. Therefore, the polysiloxane was used as RTC-imprint resist material, and also used as electron beam (EB) resist (oxide mask) material in EB lithography. We have fabricated the cylindrical GC nanodot mold with 500 nm-diameter, 600 nm-height and 2 μm-pitch. We carried out RTC-NIL using GC mold under the following optimum conditions: time from spin-coating to imprint of 1 min, imprinting pressure of 0.5 MPa and imprinting time of 5min. Then, we have processed the diamond film with an electron cyclotron resonance (ECR) oxygen ion shower. We have fabricated diamond nanopit array with 250 nm-depth and 500 nm-diameter. The diameter of diamond nanopit pattern was in good agreement with that of GC mold. Moreover, the depth of the diamond nanopit patterns fabricated by RTC-NIL using cylindrical GC mold was three times larger than that using conical diamond mold.

We report the deposition and field emission properties of nanostructured composites consisting of carbon nanowalls (CNWs) and nanocrystalline diamond films by introducing two kinds of substrate scratching pretreatment, i.e., undulation and ultrasonic vibration. With increasing duration of scratching pretreatment, the morphology of the deposits changes from simple CNWs to a film/CNW composite and lastly to CNWs on a film, and then the space between the walls is increased. The emission turn-on field is reduced from 2.1 V/μm for simple CNWs to around 1.2 V/μm for the composite films, accompanied by an increase in field enhancement factor. The results indicate that electric field screening between the walls is successfully suppressed by widening of the wall spacing.

In its relatively short history as a Raman laser material, CVD diamond has already demonstrated to be a forerunner in performance. Yet the more outstanding properties of the material such as its high thermal conductivity and wide transmission range remain largely unexploited. This paper summarizes the recent studies aimed to extend diamond laser capability beyond that readily achievable using other materials, focusing on in particular diamond Raman lasers in the ultraviolet, infrared and at high average powers.

CVD polycrystalline diamond surfaces were etched using reactive ion etching system with either a conventional stainless steel electrode or MgO sintered ceramic containing electrode. The micro-needle array of high aspect on diamond substrate surfaces obtained with MgO electrode was fabricated by using back-sputtering from MgO electrode. The RMS roughness of diamond substrate surfaces obtained with MgO electrode is higher than those obtained with stainless steel electrode.

Field electron emission model of hydrogen-terminated n-type diamond was discussed. Ultra-violet photoelectron spectroscopy characterizations indicated that the electron affinity was -0.7 eV and an internal barrier of about 3.5 eV existed on the surface. Field electron emission properties depended on anode-diamond distances. Schottky barrier lowering model suggested that this internal barrier was lowered by the electric field (5.4x106 V/cm) applied onto the negative electron affinity surface of the H-terminated n-type diamond.

Comparative study of boron doped micro/nanocrystalline diamond (BDD/BDND) electrodes was performed using electrochemical impedance spectroscopy measurements (EIS). The morphological and structural characterizations of BDD/BDND films were analyzed by scanning electron microscopy and Raman scattering spectroscopy. The films were grown with different boron amounts added in the feed gas. The boron source for BDND was smaller in concentration than that for BDD sample. Nonetheless, differential capacitance (Mott-Schottky plots) and heterogeneous charge transfer constant results showed similar doping level for both electrodes. This behavior indicated the high efficiency to dope nanocrystalline diamond films.

The fabrication of low-dimensional diamond materials in form of nanowires is a stringent requirement for advanced electronic applications. However, the nanometric control of diamond materials into desired and tailored geometries, as those ones required for applications in the field of nano-photonics, is a really challenging and complex task using currently available processes. In the present paper we describe some recent results obtained using plasma-induced processes for the shaping of diamond films in fascinating 1D structures, such as nanowires, nanowhiskers and nanopillars, to be integrated in devices of technological interest.

Nanocrystalline diamond (NCD) films are prepared from Ar-rich/N2/CH4 and Ar-rich/H2/CH4 mixtures by microwave plasma-enhanced chemical vapor deposition, and further treated by microwave hydrogen and oxygen plasma exposures separately to enhance the wetting property. The hydrogen plasma treatment has small effect on the surface roughness, while the oxygen plasma treatment forms fine protrusions on the film surface. Results show that the wettability of the hydrogen plasma treated NCD film is nearly constant or little improvement as the polar component of the apparent surface free energy is close to the as-deposit NCD film. In contrast, the wettability of the oxygen plasma treated NCD film is improved dramatically such that the contact angle is reduced from 92º and 4.7º to almost 0º for water and 1-bromonaphthalene, respectively, and the polar component increases significantly to 34 mJ/m2. The low contact angle suggests that the film is considerably a cell adhesive friendly surface, which is essential in maintaining multicellular structure, and thus making it a favorable wetting surface for biological and biomedical applications.

We suggest a new method for fabricating diamond nanoclusters by employing a coaxial arc plasma gun. Diamond powder comprised of diamond nanoclusters and amorphous carbon was fabricated in vacuum and a hydrogen atmosphere, and the diamond crystallite sizes were estimated to be 1.8, 2.3, and 2.3 nm for the powders prepared at hydrogen pressures of 0, 53.3, and 159.6 Pa respectively, from the X-ray diffraction peaks. The hydrogen ambient gas is not necessarily required for the diamond nanoclusters formation. We consider that this method enables us to form diamond nanoclusters in nucleation owing to a supersaturated condition at a facing plate located in front of an arc plasma gun.

Focused ion beam (FIB) milling of diamonds has been investigated in various ways to create desired structures on diamonds, but not much research has been reported on the effects of crystal orientation, i.e. {100}, {110} and {111} of diamonds on FIB milling. In our previous work, it was noted that focused ion beam milling may develop preferred etched directions related to the crystal orientation of crystalline diamonds. In order to further investigate the phenomenon, a focused beam of 30 kV Ga+ ions was utilized to generate various patterns on different crystallographic planes of single crystalline diamonds. The morphology of milled patterns has been monitored with various ion currents to find the relationship between crystal orientations of diamonds and their impacts on FIB milled patterns. The work showed significant differences in deformation among different crystal orientations of the single crystal diamond, and the largest area of milling in {111} crystallographic planes.

Organic light-emitting devices (OLEDs) have attracted a lot of attention as a next generation display. In this study, we fabricated the micro-OLEDs by room-temperature curing nanoimprint lithography (RTC-NIL) using diamond molds. The diamond has superior durability and was used as mold material for RTC-NIL. The diamond molds have been fabricated by electron cyclotron resonance (ECR) oxygen ion shower with polysiloxane oxide mask in the electron beam (EB) lithography technology. We fabricated the diamond mold pattern with 10 μm-square dot. The diamond molds have been used to form an insulating layer in micro-OLEDs. The optimum thickness of N,N’-Diphenyl-N,N’-di(m-tolyl)benzidine (TPD) [hole transport layer],Tris(8-quinolinolato)aluminum (Alq3) [electron transport layer] and aluminum (Al) [cathode] were 40 nm, 40 nm and 200 nm, respectively. We succeeded in formation of insulating layer in micro-OLEDs and operation of micro-OLEDs with 10 μm-square-dot by RTC-NIL using diamond molds.

High quality single crystal boron-doped diamond films are deposited in a microwave plasma-assisted CVD reactor with feedgas mixtures including hydrogen, methane, diborane, and carbon dioxide at reactor pressures of 160 Torr. The effect of diborane levels and other growth parameters on the incorporated boron levels are investigated, and the doping efficiency is calculated over a wide range of boron concentrations. The boron level is investigated using infrared absorption, and compared to SIMS measurements, and defects are shown to affect the doping uniformity.

As technology advances, ever smaller wires are needed for devices, for applications in electronics, medicine, and clean energy. Many of these applications will require the precise control of not only wire shapes and diameters, but alloy compositions as well. The recently developed technique of Electroplate-and-Lift (E&L) Lithography developed by our group has demonstrated the capability of quickly and easily producing patterned micro- and nanowires of a large variety of electrodeposited materials. Here we report the first E&L- based synthesis of microwires with controlled alloy compositions, in the model system of bronze.

Wires of several different compositions, ranging from 100% copper to 100% tin, were deposited on patterned ultrananocrystalline diamond (UNCD)TM templates, by varying the relative concentrations of copper and tin salts in the plating solution. All wires were deposited at 55oC, -1.0 V vs. the saturated calomel electrode (SCE). Wire morphology and elemental composition was observed with scanning electron microscopy (SEM) equipped with energy-dispersive spectroscopy (EDS). For some alloy compositions, wires were interrupted at irregular intervals by nodules. All alloy wires were highly enriched in copper relative to the solution composition.

The influence of anodic and cathodic pre-treatment on boron doped diamond (BDD) surface for copper (Cu) electrodeposition was studied to assess Cu particle consolidation on BDD electrode. These modified electrodes were applied to study the nitrate electrochemical reduction process. The obtained results showed that the BDD surface cathodically treated presented high Cu particle density as well as even distribution on the electrode surface after the electrodeposition process. For samples anodically treated the electrodeposited Cu was dispersed with lower particle density. This behavior was attributed to a high electrode conductivity imposed by the cathodic pre-treatment leading to an increase in the BDD surface hydrogenation. Therefore, one can conclude that for electrochemical nitrate reduction the anodically treated BDD has a better reproducibility. This response is attributed to the Cu particle consolidation on BDD electrode due to the oxygen surface terminations induced by the anodic pretreatment.

The present paper reports the utilization of a boron-doped nanocrystalline diamond film (BDD) in electrochemical oxidization (ECO) process of organic phenol compound in 0.1 M H2SO4 water solution. The nano BDD films were synthesized by microwave plasma chemical vapor deposition (MWPCVD), and then characterized by Raman spectroscopy and SEM before and after the electrochemical oxidation treatment. For the ECO treatment performed to the test sample solution, an observation of the first and the last voltammetric plots exhibited a qualitatively differences between the two plots where the first one represent the initial concentration and the last one the signal produced by the organic solution after treatment. UV-Vis analysis through the application of a standard calibration curve, quantitatively confirmed the composition of phenol remaining in the sample solution subdued to the ECO treatment.