Effect of ion implantation layer on adhesion of DLC film by plasma-based ion implantation and deposition

High adhesive diamond-like carbon (DLC) film on SUS304 was obtained using carbon ion implantation between DLC film and substrate material by plasma-based ion implantation and deposition (PBIID). Implantation of mixed silicon and carbon ions to the substrate resulted in much higher adhesion strength than that of the epoxy resin. Effect of ion implantation on adhesion of DLC film was studied by cross sectional STEM observation and EDS element analysis. Enhancement in adhesive strength by ion implantation of mixed carbon and silicon was ascribed to the formation of the multilayer interface consisting of mixed carbon and silicon ion implanted layer and the amorphous layer of carbon and silicon.     

Wear characteristics of diamond-coated atomic force microscope probe

In atomic force microscope (AFM) applications, the wear of the probe is undoubtedly a serious concern since it affects the integrity of the measurements. In this work, wear tests were performed using an AFM with lateral force monitoring capability with the aim to better understand the wear characteristics of diamond-coated probes. For the assessment of the probe wear, a transmission electron microscope (TEM) as well as a scanning electron microscope were utilized. The degree of the probe wear was quantified using the Archard's wear equation. The structure of the diamond-coated probe was analyzed by using the TEM and Raman spectroscopy. From the experimental results, two different wear characteristics, the gradual wear and the abrupt fracture of the diamond coating, were observed. In the case of gradual wear, the wear coefficient of the diamond-coated probe slid against a silicon nitride specimen was about 10(-5)-10(-6). It was also found that the wear rate significantly decreased with increase in the sliding distance. Raman spectroscopy analysis showed that the difference in the chemical structure of the diamond coating may induce the different wear phenomena. These results may be effectively utilized for fundamental understanding of nano-wear characteristics of AFM probes.     

Effects of saccharin and cobalt concentration in electrolytic solution on microhardness of nanocrystalline Ni-Co alloys

Cobalt content, surface morphology and microhardness of nanocrystalline Ni-Co deposits prepared by pulse plating technique at constant electrodeposition conditions with varied concentration of saccharin and cobalt sulfate in the electrolyte were investigated. It is found that appropriate amount of both additions could lead to finer structure and higher hardness of the deposit and further increase of the concentration could result in decline of the hardness, which is regarded as the result of inverse Hall-Petch relation. The maximum hardness of the Ni-Co alloy deposits is not higher than that of their pure Ni counterparts, indicating that the refinement hardening effect (Hall-Petch relation) is dominant in nanocrystalline Ni-Co alloy deposits. By adding Co ions to the electrolyte, the amount of organic refiner saccharin (responsible for introduction of sulfur and carbon impurities) needed to produce nanocrystalline deposits could be remarkably reduced.     

X-ray reflectivity studies on DLC films deposited by microwave ECR CVD: Effect of substrate bias

Diamond like carbon (DLC) films were deposited at room temperature on Si (111) substrates by microwave electron cyclotron resonance (ECR) plasma chemical vapor deposition (CVD) process using plasma of methane diluted with argon gas. During deposition, dc self bias (− 25 V to − 200 V) on substrate was varied by application of RF power to the substrate. The influence of substrate bias on density of the deposited films was studied by X-ray reflectivity (XRR). The results from these measurements are further correlated with the results from UV and visible Raman spectroscopy. DLC film is modeled as a structure having three different layers such as low density surface, bulk and interface with the substrate. This three-layer model is used to fit the measured XRR data to evaluate the surface, interface and interlayer roughness, thickness and density of these films. The surface roughness obtained from XRR is correlated with the results from Atomic Force Microscopy (AFM) measurements. The observed results are explained based on the subplantation model for DLC film growth.     

电源SPD在线运行安全问题及解决方案

论述低压配电系统用SPD在线运行过程中可能出现的电气故障,及由此引发的其他安全问题,分析SPD的Uc值、通流容量、Up值的选取、SPD级间能量配合及产品选型时应注意的事项。     

Effects of the polarity of bias voltage on the electrical performance of the diamond film detectors

The effect of the polarity of the applied bias voltage on the electrical response and the charge collection efficiency of sandwich structural diamond film detectors under 5.5 MeV ²⁴¹Am alpha-particle irradiation is investigated. Results show that, under the alpha irradiation the detector applied with a negative bias voltage has a higher response current and a better signal-to-noise ratio than that applied with a positive bias voltage. A better energy resolution of about 25.0% is obtained for the detector applied with a negative bias voltage, and however 38.4% for that with a positive bias voltage. Raman scattering studies demonstrate that these changes with the polarity of the bias voltage may be attributed to the different structural imperfection distributions along the thickness direction of the diamond film.     

Influence of texture on optical and electrical properties of diamond films

The optical and electrical properties of variously textured diamond films have been investigated in this paper. SEM and Raman spectrum indicated that the films produced were of high quality with either (0 0 1) or (1 1 1) orientation. A four-layer model was used to fit the measured spectroscopic ellipsometry data. The results indicated that the properties of (0 0 1)-oriented diamond films were superior to those of (1 1 1)-oriented one. The refractive index and extinction coefficient of (0 0 1)-oriented diamond film in the infrared region of 2500-12500 nm was measured as 2.391 and of the order of 10⁻⁵, respectively and that for (1 1 1)-oriented one was 2.375 and of the order of 10⁻⁴, respectively. The dark current of the (0 0 1)-oriented diamond film was measured as 33.7 nA for an applied electric field of 100 kV cm⁻¹, its resistivity being about 2.33×10¹⁰ Ω cm. Current passing through the (0 0 1)-oriented diamond film during testing did not change significantly.     

A method for very low fluence implantations using Rutherford scattering

A simple method for extremely low fluence ion implantation is described. It is based on implanting ions which are Rutherford backscattered (RBS) from a thin gold layer into the desired target. This method enables ion implantations to be carried out, as are needed to realize quantum centers on the atomic scale to serve as qubits and other nano sized devices. The required implantation fluences are orders of magnitude below the commonly-used current integration capabilities; hence control on the implanted fluence is usually complicated. The described method enables control on the implanted fluence even when extremely low. The dependence of the energy and fluence of scattered ions on the angle and scattering target thickness is analyzed by using SRIM simulations. These are verified for the case of N scattering implantation by direct counting in a surface barrier detector and for the case of Xe by counting the tracks that scattered and implanted Xe ions leaved in HOPG as viewed by scanning probe microscopy.     

Positronium molecule confined by a two-dimensional parabolic potential

A positronium molecule in two spatial dimensions and further laterally confined by a parabolic potential was investigated. By numerical diagonalization of the hamiltonian, the eigenenergies of the ground and low-energy excited states with L = 0 and 1 were calculated to study how their ordering depends on the confinement strength and symmetry of the eigenstates.