Diamond Films For Applications Research Articles

Research on the epitaxial direction control and mechanism of polycrystalline diamond grains

The control of diamond film growth is crucial for the application of diamond films. In this article, different diamond film samples were prepared by adding nitrogen and oxygen in different proportions during the growth process. The key conditions for controlling the growth of diamond film with preferred orientation were obtained using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman spectroscopy characterizations. During the growth process, the growth of the diamond film with (100) preferred orientation could be achieved by adjusting nitrogen content. It was necessary to introduce nitrogen and oxygen in the growth process, and precisely regulate the ratio of the two to obtain the (111) preferred orientation of the diamond film. When only oxygen was introduced during growth, the preferred orientation of the diamond could not be achieved, leading to a smaller grain size and poorer crystal quality. From the perspective of grain morphology to film morphology evolution, this study obtained the crystal orientation control conditions during the diamond film growth, which has important guiding significance for the application of the diamond film. This study seeks to drive progress in the large-scale growth of readily machinable diamond and the evolution of diamond-grain optical fiber sensing through comprehensive investigations into the correlation between the preferred orientation in polycrystalline diamonds and reaction conditions.

New Insights and Latest Developments in Different Disciplines of Physics through Nanotechnology

Recent advances in physics have been made through nanotechnology that employed the nanoparticles and provide the physical and chemical basis studies of various compounds. In this regards, various branches of physical such as atomic, molecular, nuclear, thermodynamics and photonics all also made several recent perspectives in their main areas. Many photonics based objected have been designed through advances in nanotechnology for example, nature of opto-electronics as it now becomes possible to imagine using coherent light produced on a chip to control electronic interactions on the same chip. The new technologies are focusing on the development of quantum physics has applied to the nanoscale systems in order to understand the as quantum sensing. Molecular physics associated with combinations of the nanoparticles intergraded with atoms and hybrid systems that would be helpful for the ultrasensitive sensor devices that are most efficient and no environmental hazards while some of the old and traditionally used devices and machines are poorly understood with noise pollution and no significant in their preparations. As, quantum computing is based on physical materials, the choice of material is important and semiconductor materials. The newly solar cell technology has been also folding the nanoparticles coating to the adhered materials of the solid surfaces for when surface plasmon is located in front of a solar cell. Microwave plasma-enhanced also applied for the different applications of diamond films. X-ray diffraction for thermodynamic based materials also important because of the some phenomenon happening in nature deals with heat, work and temperature, and their relation to energy.

Trends in Synthetic Diamond for Electrochemical Applications

Trends in Synthetic Diamond for Electrochemical Applications

A novel approach of deposition for uniform diamond films on circular saw blades

Uniform diamond films are highly desirable for cutting industries, due to their high performance and long lifetime used on cutting tools. Nevertheless, they are difficult to obtain on cutting tools with complicated shapes, greatly limiting the applications of diamond films. In this study, a novel approach of deposition for uniform diamond films is proposed, on circular saw blades made of cemented carbide using reflectors of brass sheets. Diamond films are deposited using hot filament chemical vapor deposition (HFCVD). A novel concave structure of brass sheets is designed and fabricated, improving the distribution of temperature field, and overcoming the disadvantages of the conventional HFCVD systems. This increases the energy efficiency of use without changing the structure and increasing the cost of HFCVD. The grains are refined and the intensities of diamond peaks are strengthened obviously, which is confirmed by scanning electron microscopy and Raman spectra respectively.

Dedication

Dedication

Hall effect of different textured CVD diamond films

Due to its smoothest surface, fewer defects, and better crystal quality, [100] textured diamond film is well suited for the application of optoelectronic and microelectronic devices. Carrier concentration and mobility are very important parameters of semiconductor materials. In order to further broadening the application of diamond films in optoelectronics and microelectronics, it is necessary to made a research on Hall effect characteristics of [100] textured and [111] textured films. In this paper, different textured polycrystalline diamond films are deposited on silicon substrates by hot filament chemical vapor deposition (HFCVD) method under different conditions. Microstructures of diamond films are characterized by X-ray diffraction (XRD). High quality [100] textured and [111] textured diamond films are obtained. Dark current-voltage (I-V) characteristics of different-oriented films after annealing are investigated at room temperature. The carrier concentration and mobility of diamond films are measured by Hall effect test system as the temperature changing from 100 to 500 K. Results indicate that the textures of diamond films affect the value of carrier mobility:carrier concentration increases and mobility decreases with the decrease of temperature; and the deposited films are of p-type materials. The carrier concentration and mobility of polycrystalline [100]-textured diamond films at room temperature are 4.3×104 cm-3 and 76.5 cm2/V·s, respectively.

Single-crystal diamonds for neutrons

Single-crystal Chemical Vapour Deposition (CVD) diamond detectors feature a superb Signal-to-Noise ratio (S/N , timing response and good energy resolution. These properties make CVD diamonds interesting for neutron detection. In the present contribution we discuss different measurements of neutron energy with CVD diamonds applied to relatively low- and high-energy neutrons. For the low-energy range a compact neutron Time-of-Flight (ToF) spectrometer for high flux environments has been developed. Such a detector would allow the measurement of neutron spectra in the range from 250keV up to few MeV with 20–40% resolution in the neutron fluxes 105 < φn < 109 n/cm2/s. The first prototype of this spectrometer was tested at ENEA FNG 3MeV quasi-monochromatic neutron beam and demonstrated feasibility of the concept. However, the test evidenced inadequacy of existing amplifiers providing insufficient timing resolution to extract a sensible neutron spectrum in MeV range. This particular diamond detector application, among with many others, calls for a development of a fast amplifier featuring an order of magnitude higher Signal-to-Noise ratio. On the other hand, to measure the neutron flux in a wide neutron energy range (1–100 MeV) at counting rate ∼ 2 MHz a single diamond crystal coupled to a fast (tens of ns) shaping preamplifier was used. The test performed at the n_TOF neutron beam line at CERN revealed the capability of using such a detector for spectroscopic measurement: the energy resolution achieved is about 4% at the n-α peak at 9.3 MeV, i.e. for 15 MeV neutrons. CVD diamond detectors have been proposed, successfully tested and applied as neutron flux monitors in nuclear reactor and around tokamaks. Furthermore, the possibility to extend the application of diamond films to neutron spectroscopy for a wide range of applications can be envisaged and already tested in fusion tokamak and around accelerators.

Fabrication of Antireflection Nanodiamond Particle Film by the Spin Coating Deposition Technique

Diamond-based antireflective (AR) coatings were fabricated using a spin coating of diamond suspension at room temperature as nucleation enhancement procedure and microwave plasma enhanced chemical vapour deposition. Various working pressures were used to investigate their effect on the optical characterization of the as-deposited diamond films. Scanning electron microscopy (SEM) and atomic forced microscopy (AFM) were employed to analyze the surface properties of the diamond films. Raman spectra and transmission electron microscopy (TEM) also were used for analysis of the microstructure of the films. The results showed that working pressure had a significant effect on thickness, surface roughness, and wettability of the as-deposited diamond films. Deposited under 35 Torr or working pressure, the film possessed a low surface roughness of 13.8 nm and fine diamond grain sizes of 35 nm. Reflectance measurements of the films also were carried out using UV-Vis spectrometer and revealed a low reflectance value of the diamond films. The achievement demonstrated feasibility of the proposed spin-coating procedure for large scale production and thus opens up a prospect application of diamond film as an AR coating in industrial optoelectronic device.

진공조의 잔류산소가 입방정질화붕소 박막 합성에 미치는 영향

c-BN(cubic boron nitride) is known to have extremely high hardness next to diamond, as well as very high thermal and chemical stability. The c-BN in the form of film is useful for wear resistant coatings where the application of diamond film is restricted. However, there is less practical application because of difficult control of processing variables for synthesis of c-BN film as well as unclear mechanism on formation of c-BN. Therefore, in the present study, the structural characterization of c-BN thin film were investigated using B4C target in r.f. magnetron sputtering system as a function of processing variables. c-BN films were coated on Si(100) substrate using B4C (99.5% purity). The mixture of nitrogen and argon was used for carrier gas. The deposition processing conditions were changed with substrate bias voltage, substrate temperature and base pressure. Fourier transform infrared microscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) were used to analyze crystal structures and chemical binding energy of the films. In the case of the BN film deposited at room temperature, c-BN was formed in the substrate bias voltage range of �400 V~ �600 V. Less c-BN fraction was observed as deposition temperature increased and more c-BN fraction was observed as base pressure increased.

Exploring tribological behaviour of diamond film by hot-filament chemical vapour deposition on tungsten carbide for lunar exploration

To explore the future application of diamond films coated by hot-filament chemical vapour deposition on tungsten carbide for lunar exploration, a comparative study of tribological behaviour of the film sliding in air and in vacuum under four different temperatures was conducted. Results showed that the coefficient of friction (COF) in air basically decreased with elevated temperature and, in vacuum, increased initially followed by a decrease with elevated temperature. The diamond film surface in air was observed to be smooth at 50 °C and to form a passivation layer that reduces friction at 250 °C. Its counterpart in vacuum was observed: (i) to adhere with debris at 50 °C, (ii) to form a transfer layer by the agglomerated debris at 250 °C, which reduced the friction and increased the level of agglomeration with the elevated temperature, (iii) to crack at 450 °C which subsequently increased the sliding friction. Surface graphitization of diamond was favourable in reducing the COF and detected for the sliding both in air and vacuum when the temperature was approaching 650 °C.

Study on the Deposition and Characterization of Nanocrystalline Diamond Composite Films

Nanocrystalline diamond composite films were fabricated on the WC-Co substrates using a bias-enhanced hot filament CVD system. Methanol solution pretreatment method for removing the Co in surface of WC-Co substrates was put forward. The composite structure was achieved by regulating the concentration of Ar in a mixture of acetone and a hydrogen gases in different stages. The surface morphologies, nucleation density, diamond films and composition of the nanocrystalline diamond composite films were observed with different techniques. The results showed that the introduction of Ar increased the second nucleation of diamond grains which made the diamond grains finer. Nanocrystallie diamond film can be successfully grown on the microcrystalline diamond films. The two-layer structure has the advantages of good adhesive strength and low surface roughness. Because of nano effects, the hardness of composite films decreases. This is prone to be polished and reduces the work load significantly. It is of great importance for the wide application of diamond films in the precision machining fields.

High-Q Microcavity in Two-Dimensional Diamond Photonic Crystal Thin Films Realized via a Mode Gap

We design high quality factor (Q) photonic crystal microcavities in diamond films for applications in quantum information based on color centers. A photonic microcavity made from a waveguide heterostructure with a mode gap is demonstrated to have a high Q factor over 1051400 and a modal volume V of 2.24 cubic wavelengths by modifying the mode gap width and the tapered region geometry. Besides its ultrahigh Q factor, the waveguide-like geometry of the cavity allows for easy on-chip transportation of quantum information between different cavities.

The impact of diamond nanocrystallinity on osteoblast functions

Nanocrystalline diamond has been proposed as an anti-abrasive film on orthopedic implants. In this study, osteoblast (bone forming cells) functions including adhesion (up to 4 h), proliferation (up to 5 days) and differentiation (up to 21 days) on different diamond film topographies were systematically investigated. In order to exclude interferences from changes in surface chemistry and wettability (energy), diamond films with nanometer and micron scale topographies were fabricated through microwave plasma enhanced chemical-vapor-deposition and hydrogen plasma treatment. Scanning electron microscopy (SEM), atomic force microscopy (AFM), Raman spectroscopy and water contact angle measurements verified the similar surface chemistry and wettability but varied topographies for all of the diamond films prepared on silicon in this study. Cytocompatibility assays demonstrated enhanced osteoblast functions (including adhesion, proliferation, intracellular protein synthesis, alkaline phosphatase activity and extracellular calcium deposition) on nanocrystalline diamond compared to submicron diamond grain size films for all time periods tested up to 21 days. An SEM study of osteoblast attachment helped to explain the topographical impact diamond had on osteoblast functions by showing altered filopodia extensions on the different diamond topographies. In summary, these results provided insights into understanding the role diamond nanotopography had on osteoblast interactions and more importantly, the application of diamond films to improve orthopedic implant lifetimes.

Design of Photonic Crystal Microcavities in Diamond Films

We design photonic crystal microcavities in diamond films for applications in quantum information. Optimization of the cavity design by "gentle confinement" yields a high quality factor Q>66000 and small mode volume V approximately 1.1( l/n)(3). In view of experimental applications we consider the influence of material absorption on the cavity Q factors and present a simple interpretation in the framework of a one-dimensional cavity model.

Laser induced damage for diamond films

The outstanding optical and mechanical properties of diamond films are summarized. Laser damage for films irradiated with different wave lengths and pulse width are reviewed and the laser damage mechanism analyzed for different parameters. It is found that graphitization induced instability of the crystal lattice is the main reason for laser induced damage. There are two ways that lead to graphitized damage on the surface of diamond films under long and short laser pulses. For nanosecond or longer laser pulses, graphitization propagates vertically into the bulk of the diamond films. For femtosecond laser pulses, graphitization occurs on the surface of the diamond films layer by layer. Based on the physical properties and preparation technology, practical and promising applications of diamond films are proposed.

Application of diamond film to cold cathode fluorescent lamps for LCD backlighting

A cold cathode fluorescent lamp (CCFL) is a gas discharge light source widely used for liquid crystal display (LCD) backlighting. We proposed applying diamond as a new cathode material to reduce the power consumption of the CCFL. In this work, we show stable and low (less than 50% of metal) cathode-fall voltage for a glass discharge tube.

The influence of dark feature on optical and thermal property of DC Arc Plasma Jet CVD diamond films

Different grades of CVD diamond films were prepared by 100 kW DC Arc Plasma Jet system. The films were characterized using optical microscope (OM), high-resolution transmission electron microscopy (HRTEM), electron energy-loss spectroscopy (EELS), and Raman spectroscopy. The results show that dark feature mainly is inclusions in CVD diamond films, the concentration are amorphous carbon and nitrogen. As for transparent optical grade diamond film, it has very high IR transparency and high thermal conductivity. The appearance of dark feature degraded the quality of CVD diamond film, apparently influencing IR transparency and thermal conductivity. But even in optical grade diamond film, there are very strong absorption features in the 7–9 μm region, this will limit the practical applications of diamond films grown by Plasma Jet as IR windows for CO 2 lasers.

Development of Ultra Fine Crystalline Diamond Film and Some Applications

We would like to report on the development of our new ultra fine crystalline CVD diamond film and some applications. CVD Diamond films have good wear resistance, but the crystal size is too large. Therefore, in case of application of diamond films for cutting tools, we cannot get fine surface finish on work materials. Recently we succeed in production ultra fine crystalline CVD diamond film and various cutting tools as taps, drills and end mills. Aluminum alloys have lately been consumed more than ever in airplanes and automobiles for the purpose of decreasing the weight of structural materials.Copper alloys are used for the electrode of electric discharge machines (EDM) recently. EDM electrodes are required fine surface finish because the surface quality of mold depends on accuracy of EDM electrodes. Soft materials such as aluminum and copper alloys have high viscosity and additionally activity. So during cutting aluminum and copper alloys we have sometimes adhesion between cutting tools and work pieces. Diamond film on tools is able to improve the reactivity to aluminum and copper alloys. But up to now the diamond film has a lot of course crystal and tend to supply rough surface finish on work pieces. We developed ultra fine crystalline diamond film on end mills by plasma chemical vapor deposition (CVD) method. Now our aircraft, automotive and molding customers can get smooth surface finish of work pieces.Keeping ISO14001, we recommend oil free cutting with ultra fine crystalline diamond coated cutting tools. Here I introduce background of the development and cutting examples with new fine diamond coated end mills.

Application of Diamond film on ceramics components for plasma process

Application of Diamond film on ceramics components for plasma process

Friction force microscopy study of diamond films modified by a glow discharge treatment

Abstract A glow discharge treatment technique has been developed which enables control of the surface roughness and morphology of diamond films for applications in optical and electrical components. A conventional hot filament chemical vapour deposition (CVD) system was used to deposit the diamond films onto silicon substrates via a three-step sequential process: (i) deposition under normal conditions; (ii) exposure to either a pure hydrogen plasma or 3% methane in an excess of hydrogen using DC-bias; and (iii) diamond deposition for a further 2 h under standard conditions. The frictional characteristics and roughness of the film surfaces were investigated by atomic force microscopy (AFM) and the morphology and the growth rates determined from scanning electron microscope images. Lateral force microscopy (LFM) has revealed significant differences in frictional behaviour between the high quality diamond films and those modified by a glow discharge treatment. Friction forces on the diamond films were very low, with coefficients ∼0.01 against silicon nitride probe tips in air. However, friction forces and coefficients were significantly greater on the DC-biased films indicating the presence of a mechanically weaker material such as an amorphous carbon layer. A combination of growth rate and frictional data indicated that the exposure to the H 2 plasma etched the diamond surface whereas exposure to CH 4 /H 2 plasma resulted in film growth. Re-Nucleation of diamond was possible (stage iii) after exposure to either plasma treatment. The resultant friction forces on these films were as low as on the standard diamond film.