Papers by Keyword: Electron

Abstract: In the presented work the features of formation of metal-fullerene films of the systems Al-C₆₀, Au-C₆₀, Cu-C₆₀, Ti-C₆₀ from atomic-molecular flows in vacuum were investigated, the processes of surface resonance plasmon absorption and diffusion were studied. It is shown that electron microscopy, optical, Auger-electron and X-ray spectroscopy methods are effective for the study of metal-fullerene films. The combination of different methods of spectroscopy and electron microscopy allowed to establish the dependence of the grain size of the films, the shift of the position of the plasmon absorption maximum, diffusion parameters on the ratio of metal and fullerene components, to establish the fact of formation of the chemical compound Cu₆C₆₀.

Abstract: In this study, we delve into the electromechanical characteristics of the CF monolayer using ab initio theory. The CF monolayer possesses flexible mechanical properties with relatively small elastic coefficients. Additionally, our findings reveal that the CF monolayer can sustain significant strains of up to 24% along the x-axis and 14% along the y-axis under tensile stress. The critical stresses corresponding to these strain values are 21.79 N/m and 17.46 N/m, respectively. Specifically, as the charge varies from 0.00 to -0.07 e/atom, there is an increase in the failure strain along the x-axis, from 24% at equilibrium to 30% at -0.07 e/atom. At equilibrium, the CF monolayer is identified as a direct semiconductor with a band gap of 3.21 eV. Despite charge doping, the monolayer CF retains its direct semiconductor properties. Notably, the energy band gap of the CF monolayer is dependent on charge doping and can be modified by about 10%. Furthermore, the electronic properties of the CF monolayer suggest its potential applications in spin-polarized electronics. Our results provide evidence of the applicability of the CF monolayer in electronic devices.

Abstract: Presence of Bismuth (Bi) leads to topologically nontrivial band structure in many materials, especially in topological insulators. Traditionally Bi is known to be a semimetal but, quite surprisingly, in a recent experiment bulk Bi has been found to be a superconductor below 0.53 mK at ambient pressure. In order to have a closer look at the electronic properties of bulk Bi in the wake of this unexpected experimental evidence of superconducting phase, we have performed density-functional-theory (DFT) based first principle calculations using plane-wave basis set and with suitable ionic pseudopotentials. We have computed the band structure, density of states and Fermi surfaces for two different type of exchange-correlation (XC) functionals, namely Perdew-Zunger (PZ) and Perdew-Burke-Ernzerhof (PBE) type. Each of these XC functional has been considered without and with spin orbit (SO) interaction. After carefully examining the energy-convergence with respect to plane wave basis set and k-points in each case, the band structure has been calculated along the path Γ-L-T-Γ. Without SO coupling, electron pocket is found near ‘L’ and exactly at ‘Г’ and hole pocket is at ‘T’ for PZ type XC functional, while in the case of PBE-type electron pocket is found exactly at ‘L’ but the hole pocket to be near to ‘T’. With SO coupling, in PZ-type, electron pocket remains at same position, but hole pocket appears only at ‘Г’ point. Finally, when SO coupling is taken into account along with PBE-type XC functional electrons and holes are found at ‘L’ and at ‘T’ respectively. Furthermore, in this case we also observe an increase in the number of holes at ‘T’.

Abstract: The electrical behaviour of irradiated and post-irradiation annealed nMOSFETs with an implanted p-type body and having a N₂O oxynitrided gate oxide is analysed in this work. This study reveals the existence of a “threshold fluence” which might change the predominant SiO₂/SiC interface charge trapping type from donors to acceptors at a given energy. The irradiation fluence and energy limit that guaranty a normal or improved operation of the MOSFETs are also given.

Abstract: The effect of 4.5 MeV electron irradiation on static characteristics of commercially available 5 A/1700 V SiC power MOSFETs is investigated. Results show that in the low dose range (up to 20 kGy) the threshold voltage decreases rapidly with irradiation dose but devices keep full functionality. This effect is caused by embedding of the positive charge into the gate oxide. When electron dose reaches 200 kGy, the threshold voltage moves back close to its original value, however, the ON‑state resistivity increases and transconductance is lowered. This is caused by introduction of deep acceptor centers into the low doped drift region of MOSFET. This effect can be considered as a cause of the final failure of the device (the lost of the ON-state capability).

Abstract: A fundamental study on finishing aided by an ultraviolet ray (generally mashining:referred to as U-RAM^R) was conducted to evaluate its applicability to the polishing of aluminum alloy. Qualitative analysis with X-ray photoelectron spectroscopy (XPS) was used to estimate the chemical reaction induced on Al surfaces that were immersed in some solutions. Inductively coupled plasma spectroscopy (ICPS) was employed to quantitatively analyze the amount of oxidized/dissolved Al, Mg and Fe. The following conclusions were obtained by investigation of the aluminum alloy polishing process. Aluminum does not dissolve in TiO₂-solution, whereas a small amount of Al dissolves into cathilon dye solution. Although only a small amount of Al dissolves in TiO₂-cathilon dye solution in the absence of UV irradiation, the amount of Al dissolved increases slightly under UV irradiation with the formation of oxide, nitrogen oxide and nitride on the Al surface. In addition, a small amount of an aluminum chloride dissolves into TiO₂-cathilon dye solution. An Al alloy (A5052) surface was made flat by polishing with TiO₂-cathilon dye slurry under UV irradiation.

Abstract: 4H-SiC Schottky barrier diodes (SBDs) were irradiated to neutron fluence of 3.55 x10¹⁶ cm^-2 and 6.6 x 10¹⁵ cm^-2 (15,000 kGy) electrons respectively. In general, characterization of the irradiated samples show that the current characteristics of the diodes decreased. The performance of Schottky gate contact is less for electron irradiated sample compared to neutron irradiated sample. The d-spacing, crystallite sizes and lattice strains were calculated from X-ray diffraction (XRD) measurements. SiC Schottky interface damage and radiation defects, as observed in atomic force microscopy (AFM) topography and scanning electron microscope (SEM) morphology images is possibly the main reason for this reduction in performance.

Abstract: Auger electron spectroscopy (AES) and electron energy loss spectroscopy (EELS) studied the interaction of argon ions with a natural oxide layer of polycrystalline aluminum. It was found that the bombardment of argon ions with an energy lower sputtering threshold Al₂O₃ leads to accumulation of ions bombarding the interstitial voids in the surface, thereby forming a solid solution of atoms of the target, the argon ions and nitrogen ion beam, the captured residual gas from the chamber of the spectrometer.

Abstract: Aim at the brake fluid system cannot protect the automobile security effectively, this article analyzes the electromechanical brake system in details. At first, it introduces the theory and the advantage composition of the electromechanical brake system. Then, this article introduces the hardware of EBS system and evaluates the design of EMB electrical machine and electron pedal. At last, it particularly analyzes the system software. This article has significant meaning to the automobile maintainers and the braking system researchers.

Abstract: In this paper, the technique of irradiation of thin films by Ga+ ions inside of scanning electron microscope, by a focused ion beam is developed. The influence of irradiation on magnetic properties of thin epitaxial films of Co, grown by molecular beam epitaxy in ultrahigh vacuum on a silicon surface with a intermediate layer of copper atoms. It has been shown that low radiation doses lead to an increase of magnetic hardness of the samples. At higher doses, there is a decrease of coercive force, which is apparently due to a change of crystalline structure of the material. An interesting fact is that in the dose range of 10¹²-10¹⁵ the relative remanences is practically unchanged and only at higher doses the magnetic properties of the film worsen.