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Production of a laser textured 316L stainless steel reinforced with CuCoBe + diamond composites by hot pressing: Influence of diamond particle size on the hardness and tribological behaviour
摘要： Two composite blends of CuCoBe and synthetic diamond with different particle sizes, (0.1-0.5 μm and 40-60 μm), were obtained by mechanical alloying and were used as a reinforcement of a laser textured 316L stainless steel in this work. Consolidation/sintering of the powders was conducted by hot pressing. From all the samples studied, the 316L stainless steel reinforced with the CuCoBe + diamond (40-60 μm) composite presented the lowest values of specific wear rate and coefficient of friction (5.83 x 10-7 mm3/N.m and 0.14, respectively), showing the potential of this material in applications where good tribological behaviour is required, e.g. for the fabrication of improved automotive piston rings.
关键词： laser texturing,Diamond composites,tribological behaviour,hot pressing
更新于2025-09-12 10:27:22
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Fast smoothing on diamond surface by inductively coupled plasma reactive ion etching
摘要： The synergetic effects of surface smoothing exhibited during the inductively coupled plasma reactive ion etching (ICP-RIE) of free-standing polycrystalline diamonds (PCDs) were investigated. Changing the assistive gas types generated variable surface oxidation states and chemical environments that resulted in different etching rates and surface morphologies. The main reaction bond mechanism (C–O) during ICP-RIE and the ratio of C–O–C/O–C=O associated with the existence of a uniform smooth surface with root mean square (RMS) roughness of 2.36 nm were observed. An optimal process for PCD smoothing at high etching rate (4.6 lm/min) was achieved as follows: 10% gas additions of CHF3 in O2 plasma at radio frequency power of 400 W. The further etched ultra-smooth surface with RMS roughness <0.5 nm at etching rate of 0.23 lm/min that being produced by transferring this optimum recipe on single crystal diamonds with surface patterns confirmed the effectiveness of the fast smoothing approach and its feasibility for diamond surface patterning.
关键词： surface smoothing,diamond,etching rate,ICP-RIE,surface morphology
更新于2025-09-12 10:27:22
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Pure carbon conductive transparent electrodes synthetized by a full laser deposition and annealing process
摘要： One of the biggest challenge that face optoelectronic and photovoltaic devices is the necessity to provide a reliable alternative to transparent conducting oxide (TCO) like Indium Thin Oxide (ITO). We recently published a study proposing a method to produce transparent conductive electrodes only based on carbon materials. In a first step, we use the Pulsed Laser Deposition (PLD) to produce high performance DLC. Those thin films own very interesting properties in kindship with diamond, like high transparency in the visible range, chemical inertness and biocompatibility. In addition, the DLC is a perfect electrical insulator and presents a relative high opacity in ultra-violet (UV). This particularity has a great interest to perform, in a second step, UV laser annealing over the DLC surface. The aim is to break the existing diamond bindings (sp3 hybridization) on the surface and allow atoms being reorganized in graphitic bindings (sp2 hybridization). We demonstrate that the increase of atomic graphitic bindings leads to a valuable surface conductivity. According to optimized annealing parameters, the surface conductivity reaches values comparable to ITO. We also show that the laser treatments only sparsely affects the DLC transparency. Moreover, this full laser-based process remains compatible with the standard microelectronic technological steps.
关键词： Diamond-Like Carbon (DLC),Graphitization,Pulsed Laser Deposition (PLD),Transparent electrodes,Laser surface annealing
更新于2025-09-12 10:27:22
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Nanoplasmonic 1D Diamond UV Photodetectors with High Performance
摘要： Diamond nanowires have recently drawn substantial attention due to their unique physical and chemical properties for electrochemical sensors, optoelectronics, and nanophotonics applications. However, diamond nanowire based ultraviolet photodetectors have not been reported because of the challenges involved in synthesizing crystalline diamond nanowires with controllable morphologies and, more fundamentally, the material’s high carrier concentration with low mobilities that limits the obtainable photoresponsivity. The synergetic integration of ultrananocrystalline diamond (UNCD) nanowires with nanoplasmonic enhancement by noble metal nanoparticles is a very promising approach to overcome these shortcomings. Here we report the fabrication of boron doped ultrananocrystalline diamond nanowires functionalized with the platinum nanoparticles to form self-powered ultraviolet photodetectors that exhibit an ultrahigh photoresponsivity of 388 Amp/Watt at 300 nm wavelength, a fast response time around 20 ms, and a good UV/visible rejection ratio of about five orders of magnitude under zero-bias condition.
关键词： ultraviolet photodetector,nanowire,metal nanoparticle,ultrananocrystalline diamond,nanoplasmonics
更新于2025-09-12 10:27:22
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Plasmonic Properties of Nanostructured Diamond Like Carbon/Silver Nanocomposite Films with Nanohole Arrays
摘要： Plasmonic properties of the diamond like carbon nanocomposite films with embedded silver nanoparticles with patterned nanohole arrays were analyzed in this study. The films were deposited by unbalanced reactive magnetron sputtering of silver target. Nanopatterning of the films was performed by combining electron beam nanolithography and ion beam etching techniques. Modeling of plasmonic properties was done using the classical Maxwell-Garnett theory. Modeling data and experimental results were in good accordance. Formation of the nanohole pattern in diamond like carbon films doped with silver resulted in decreased intensity of the surface plasmon resonance absorbance peak. No new absorbance or transmittance peaks were observed after the nanopattering. It was explained by extraordinary transmission effect in nanostructured DLC : Ag film films due to plasmon polariton resonance inside of the nanoholes.
关键词： plasmon polariton resonance,nanohole array,diamond like carbon films
更新于2025-09-12 10:27:22
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Enhanced and switchable silicon-vacancy photoluminescence in air-annealed nanocrystalline diamond films
摘要： Silicon vacancy (SiV) centers in CVD-deposited nanodiamond particles or films always exhibit a photoluminescent (PL)-quenching behavior. Herein, in order to overcome this issue, air annealing of nanocrystalline diamond (NCD) films with uniform doping of Si atoms is employed to improve the PL emission efficiency of SiV centers. Without severe mass loss in diamond, SiV centers exhibit an increased PL emission intensity at 738 nm with an increased annealing temperature and time. In comparison to the untreated film, the maximum PL enhancement reaches about 200 and 1473 folds when the NCD films are annealed at 600 oC for 60 min and 700 oC for 20 min, respectively. Such giant increase in SiV PL emission is mainly attributed to the transition of diamond surface from hydrogen to oxygen termination together with the optimized crystalline quality of the annealed films, as confirmed by the HRTEM, Raman and XPS measurements. A schematic model based on the theory of surface band bending is proposed to elucidate the mechanism of the SiV PL enhancement in oxygen-terminated NCD films: a near-surface light trap layer formed in hydrogen-terminated NCD is converted during the oxidation process, leading to the additional collection of SiV PL emission from the inner layer.
关键词： thermal treatment,luminescence,surface modification,color center,nano-crystalline diamond
更新于2025-09-12 10:27:22
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Broadband visible-near infrared and deep ultraviolet generation by four-wave mixing and high-order stimulated Raman scattering from the hybrid metasurfaces of plasmonic nanoantennae and Raman-active nanoparticles
摘要： The efficient generation of a broadband frequency comb from the visible to ultraviolet region is a challenging task despite its importance for nanoscale spectroscopy and sensing applications. In this paper, we reported broadband visible-near infrared and deep ultraviolet generation by four-wave mixing and high-order stimulated Raman scattering from hybrid metasurfaces made of plasmonic nanoantennae embedded with Raman-active diamond nanoparticles as examples. Upon two-color near-infrared pumping tuned to a Raman resonance, one can generate a visible-near infrared frequency comb with a major contribution of high-order stimulated Raman scattering by the coherent modulation of the Raman medium and simultaneously, a broad deep ultraviolet frequency comb is radiated by four-wave mixing and third-harmonic generations. The efficiencies of the individual spectral peaks reached values in the order of 10?8–10?2% under pumping with pulses with a peak intensity of about 33 GW cm?2 and a duration of 100 fs in the near infrared region.
关键词： high-order stimulated Raman scattering,visible-near infrared,hybrid metasurfaces,plasmonic nanoantennae,Raman-active diamond nanoparticles,deep ultraviolet,broadband frequency comb,four-wave mixing
更新于2025-09-12 10:27:22
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Effect of Laser Ablation on Microwave Attenuation Properties of Diamond Films
摘要： Thermal conductivity is required for developing high-power microwave technology. Diamond has the highest thermal conductivity in nature. In this study, a diamond ?lm was synthesized by microwave plasma chemical deposition, and then long and short conductive graphite ?bers were introduced to the diamond ?lms by laser ablation. The permittivity of the samples in the K-band was measured using the transmission/re?ection method. The permittivity of diamond ?lms with short graphite ?bers increased. The increase in real part of permittivity can be attributed to electron polarization, and the increase in the imaginary part can be ascribed to both polarization and electrical conductivity. The diamond ?lms with long graphite ?bers exhibited a highly pronounced anisotropy for microwave. The calculation of microwave absorption shows that re?ection loss values exceeding ?10 dB can be obtained in the frequency range of 21.3–23.5 GHz when the graphite ?ber length is 0.7 mm and the sample thickness is 2.5 mm. Therefore, diamond ?lms can be developed into a microwave attenuation material with extremely high thermal conductivity.
关键词： high thermal conductivity,laser ablation,diamond ?lms,microwave attenuation,permittivity
更新于2025-09-12 10:27:22
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Tailoring of Silver Nanoparticle Size Distributions in Hydrogenated Amorphous Diamond‐like Carbon Nanocomposite Thin Films by Direct Femtosecond Laser Interference Patterning
摘要： Tailoring of Silver Nanoparticle Size Distributions in Hydrogenated Amorphous Diamond-like Carbon Nanocomposite Thin Films by Direct Femtosecond Laser Interference Patterning
关键词： diamond-like carbon,direct laser interference patterning,silver nanoparticles,ablation threshold,nanocomposites
更新于2025-09-11 14:15:04
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Diamond detector with laser-formed buried graphitic electrodes: micron-scale mapping of stress and charge collection efficiency
摘要： The paper reports the micron-scale investigation of an all-carbon detector based on synthetic single crystal CVD-diamond having an array of cylindrical graphitic buried-contacts, about 20 μm in diameter each, connected at the front side by superficial graphitic strips. To induce diamond-to-graphite transformation on both detector surface and bulk volume, direct-laser-writing technique was used. Laser-treatment parameters and cell shape have been chosen to minimize the overlapping of laser-induced stressed volumes. Optical microscopy with crossed polarizers highlighted the presence of an optical anisotropy of the treated material surrounding the embedded graphitized columns, and non-uniform stress in the buried zones being confirmed with a confocal Raman spectroscopy mapping. Dark current-voltage characterization highlights the presence of a field-assisted detrapping transport mainly related to highly-stresses regions surrounding buried columns, as well as superficial graphitized strips edges, where electric field strength is more intense, too. Notwithstanding the strain and electronic-active defects, the detector demonstrated a good charge collection produced by 3.0 and 4.5 MeV protons impinging the diamond, as well as those generated by MeV β-particles emitted by 90Sr source. Indeed, the mapping of charge collection efficiency with Ion Beam Induced Charge technique displayed that only a few micrometers thick radial region surrounding graphitic electrodes has a reduced efficiency, while most of the device volume preserves good detection properties with a charge collection efficiency around 90% at 60 V of biasing. Moreover, a charge collection efficiency of 96% was estimated under MeV electrons irradiation, indicating the good detection activity along the buried columns depth.
关键词： β-particles,3D detectors,graphitic pillars,IBIC,sc-CVD diamond,protons
更新于2025-09-11 14:15:04