E. P. Kirilenko

Formation of carbon nanotubes on an amorphous Ni25Ta58N17 alloy film by chemical vapor deposition

It is shown that it is possible to grow carbon nanotubes on the surface of an amorphous Ni–Ta–N metal alloy film with a low Ni content (~25 at %) by chemical deposition from acetylene at temperature 400–800°C. It is established that the addition of nitrogen into the Ni–Ta alloy composition is favorable for the formation of tantalum nitride and the expulsion of Ni clusters, which act as a catalyst of the growth of carbon nanotubes, onto the surface. From Raman spectroscopy studies, it is found that, as the temperature of synthesis is raised, the quality of nanotubes is improved.

Growth of vertically aligned multiwalled carbon nanotubes forests on metal alloy Ni-Nb-N with low content of catalyst

This research shows the possibility of carbon nanotubes (CNTs) formation on the surface of low nickel (~ 10 at.%) Ni-Nb-N amorphous metal alloy film by CVD method at 550 °C of the gas mixture based on acetylene. The structure of CNT were studied by transmission and scanning-electron microscopy, energy-dispersive X-ray and the Raman spectroscopy.

Mo/Ni and Ni/Ta–W–N/Ni thin-film contact layers for (Bi,Sb)2Te3-based intermediate-temperature thermoelectric elements

We have examined the possibility of utilizing thin-film contact layers for producing reliable Ohmic contacts to proposed intermediate-temperature (Bi,Sb)2Te3-based thermoelectric materials with improved thermoelectric properties, which allow the working temperature range to be extended to 600 K. Three contact configurations have been produced by ion-plasma magnetron sputtering: a single Ni layer, Mo/Ni bilayer, and Ni/Ta–W–N/Ni three-layer system. It has been shown that reliable contacts can be produced using Mo/Ni and Ni/Ta–W–N/Ni layers, which prevent interdiffusion between the materials to be joined and ensure good adhesion to the thermoelectric element.

Formation of Precipitates in Si Implanted with 64Zn+ and 16O+ Ions

The results of studying the surface Si layer and precipitate formation in CZ n-Si(100) samples sequentially implanted with 64Zn+ ions with a dose of 5 × 1016 cm2 and energy of 100 keV and 16O+ ions with the same dose but an energy of 33 keV at room temperature so that their projection paths Rp = 70 nm would coincide are presented. The post-implantation samples are annealed for 1 h in an inert Ar medium in the temperature range of 400–900°C with a step of 100°C. The profiles of the implanted impurities are studied by time-of-flight secondary ion mass spectrometry. The Si surface is visualized using a scanning electron microscope, while the near-surface layer is visualized with the help of maps of elements formed by Auger electron spectroscopy with profiling over depth. The ZnO(002) texture is formed in an amorphized Si layer after the implantation of Zn and O ions. ZnO(102) crystallites of 5 nm in size are found in a recrystallized single-crystalline Si layer after annealing in Ar at 700°C.

Study of Silicon Doped with Zinc Ions and Annealed in Oxygen

The results of studies of the surface layer of silicon and the formation of precipitates in Czochralski n-Si (100) samples implanted with 64Zn+ ions with an energy of 50 keV and a dose of 5 × 1016 cm–2 at room temperature and then oxidized at temperatures from 400 to 900°C are reported. The surface is visualized using an electron microscope, while visualization of the surface layer is conducted via profiling in depth by elemental mapping using Auger electron spectroscopy. The distribution of impurity ions in silicon is analyzed using a time-of-flight secondary-ion mass spectrometer. Using X-ray photoelectron spectroscopy, the chemical state of atoms of the silicon matrix and zinc and oxygen impurity atoms is studied, and the phase composition of the implanted and annealed samples is refined. After the implantation of zinc, two maxima of the zinc concentration, one at the wafer surface and the other at a depth of 70 nm, are observed. In this case, nanoparticles of the Zn metal phase and ZnO phase, about 10 nm in dimensions, are formed at the surface and in the surface layer. After annealing in oxygen, the ZnO · Zn2SiO4 and Zn · ZnO phases are detected near the surface and at a depth of 50 nm, respectively.

Performance of Bi2Te3 Thermoelectric Element Improved by Means of Contact System Ni/Ta-W-N/Ni

In this paper the materials with improved thermoelectric properties developed based on Bi2Te3 were used for the production of thermoelectric generator. It allowed to extend the operating temperature range of the material to 550 K. Bi2.0Te2.4Se0.6 doped with 0.12 wt% CuBr (dimensionless coefficient ZT = 1.1 at a temperature of 450–550 K) was used as a material for manufacturing n-type branches. Bi0.4Sb1.6Te3.0 doped with 0.12 wt% PbCl2 and 1.5 wt% Te (dimensionless coefficient ZT = 1.2 at a temperature of 450–550 K) was used as a material for manufacturing p-type branches. The following materials were used as the contact system: 100 nm layer of nickel as the ohmic contact layer; 100 nm layer of amorphous alloy Ta-W-N as a diffusion barrier layer; and 400 nm layer of nickel as a wetting layer for soldering. Study of adhesion of this contact system demonstrated good quality. The breakout force was 12 MPa.

Visualization and identification of nanoparticles in si subjected to the successive implantation of 64Zn+ and 16O+ ions

Nanoparticles are visualized and identified in a near-surface Si layer subjected to the successive implantation of 64Zn+ and 16O+ ions. Scanning transmission electron microscopy coupled with energy-dispersive spectroscopy and X-ray photoelectron spectroscopy are used. An amorphized region 150 nm thick and a disturbed layer 50 nm thick in the near-surface layer of the substrate are revealed after implantation. Zinc oxide (ZnO) nanoparticles with an average size of 8.7 nm are found in the recrystallized polycrystalline silicon layer after annealing in a neutral-inert atmosphere at a temperature of 600–800°C.

Combine SAES/XPS and AFM investigation of nanoparticles in Zn+ and O+ ion sequentially implanted Si

Here we present the prolongation of our earlier studies [2] about of NPs formation in Si substrate by subsequently 64Zn+ and 16O+ ion implantation and thermal treatment. The Si substrates were implanted with dose of D=2×1016 cm-2 by 64Zn+ ions with energy of E=100 keV and 16O+ ions with energy of E=30 keV. The characterization of implanted layer and visualization of NPs formation were made by high resolution transmission electron microscopy of cross-section samples (HRTEM) and with addition of Energy Dispersive X-ray Spectroscopy (EDS) including EDS mapping using electron microscope JEM-2100 at acceleration voltage of 200 kV. The element content with profile control was determined by scan Auger electron spectroscopy (AES) using PHI-670xi unit (Physical Electronics) and X-ray photo-electron spectroscopy (XPS) using scan Multibrobe PHI-660 (Perkin-Elmer).