Engineering topics

Valeev, V. F.

Publications and source records attributed to Valeev, V. F..

7 records

DOE OSTI2019

Studying Near-Surface Layers of Germanium Implanted with Cobalt Ions

Results of an investigation of the surface of germanium nanostructured by means of ion implantation are presented. Single-crystalline germanium (c-Ge) plates were irradiated by 40-keV cobalt Co{sup +} ions in a dose range of (2–8) × 10{sup 16} ion/cm{sup 2}. Evolution of the germanium surface morphology with increasing ion dose was studied by method of scanning electron microscopy. It is established that an increase in the ion implantation dose is accompanied by gradual formation of a surface layer consisting of spherical particles with diameters of ~150 nm. Analysis of the X-ray diffraction patterns of samples was indicative of the appearance of nanosized cobalt germanide (CoGe) particles in the ion-implanted surface layer.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2019

Microscopic Examination of the Silicon Surface Subjected to High-Dose Silver Implantation

Low-energy (E = 30 keV) Ag{sup +} ions have been implanted into single-crystalline Si wafers (c-Si) with an implantation dose varying from 1.25 × 10{sup 15} to 1.5 × 10{sup 17} ions cm{sup –2} and an ion beam current density varying from 2 to 15 μA/cm{sup 2}. The surface morphology of implanted wafers has been examined using scanning electron microscopy, transmission electron microscopy, and atomic force microscopy, and their structure has been studied by means of reflection high-energy electron diffraction and elemental microanalysis. It has been shown that for minimal irradiation doses used in experiments, the surface layer of c-Si experiences amorphization. It has been found that when the implantation dose is in excess of the threshold value (~3.1 × 10{sup 15} ions cm{sup –2}), Ag nanoparticles uniformly distributed over the Si surface arise in the irradiated Si layer. At a dose exceeding 10{sup 17} ions cm{sup –2}, a porous Si structure is observed. In this case, the Ag nanoparticle size distribution becomes bimodal with coarse particles localized at the walls of Si pores.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2018

Raman Scattering of Light by Molecules of Methyl Orange Dye on the Surface of Silicon Containing Ion-Synthesized Silver Nanoparticles

The possibility of using a new composite material based on porous silicon containing silver nanoparticles and synthesized by means of a unique implantation nanotechnology as an optically sensitive material in biological and chemical sensors is tested experimentally. It is demonstrated that detection of small amounts of the studied organic substance (methyl orange dye) is possible due to the effect of surface-enhanced Raman scattering (SERS) from the molecules affected by the local electromagnetic field of the silver nanoparticles.

77 NANOSCIENCE AND NANOTECHNOLOGY↗

DOE OSTI2018

Crystal-Chemical Features of Diamonds Implanted with Helium Ions

Implantation of high-energy helium ions into crystals of natural colorless diamonds colors them bright yellow, brown, or black, depending on the implantation dose. The nature of the induced fantasy color and crystal-chemical features of the implanted diamonds have been investigated by IR spectroscopy and Raman spectroscopy. It is established that the radiation effect of helium ions on the diamond crystal structure results in the transformation of nitrogen-vacancy centers in its bulk with the formation of new A-type color centers, as well as the formation of carbon nanoclusters with the sp{sup 2} hybridization of bonds (which is typical of graphite) in black diamonds.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2018

Formation of Porous Germanium Layers by Silver-Ion Implantation

We propose a method for the formation of porous germanium (P-Ge) layers containing silver nanoparticles by means of high-dose implantation of low-energy Ag{sup +} ions into single-crystalline germanium (c-Ge). This is demonstrated by implantation of 30-keV Ag{sup +} ions into a polished c-Ge plate to a dose of 1.5 × 10{sup 17} ion/cm{sup 2} at an ion beam-current density of 5 μA/cm{sup 2}. Examination by high-resolution scanning electron microscopy (SEM), atomic-force microscopy (AFM), X-ray diffraction (XRD), energy-dispersive X-ray (EDX) microanalysis, and reflection high-energy electron diffraction (RHEED) showed that the implantation of silver ions into c-Ge surface led to the formation of a P-Ge layer with spongy structure comprising a network of interwoven nanofibers with an average diameter of ∼10–20 nm Ag nanoparticles on the ends of fibers. It is also established that the formation of pores during Ag{sup +} ion implantation is accompanied by effective sputtering of the Ge surface.

77 NANOSCIENCE AND NANOTECHNOLOGY↗

DOE OSTI2018

Temperature sensor based on a polymer diffraction grating with silver nanoparticles

The method is suggested for producing an optical temperature noncontact sensor on a polymer polymethylmethacrylate (PMMA) substrate with a diffraction optical element formed by implanting low-energy high-dose silver ions through a surface mask. Ion implantation is performed at an energy of 30 keV, a radiation dose of 5.0 × 10{sup 16} ion cm{sup −}2 and an ion beam current density of 2 μA cm{sup −}2 through a surface metal mask having the form of grid with square periodical holes (cells) of size 25 μm. In the course of implantation, silver nanoparticles are produced in periodical unmasked domains of irradiated PMMA. Operation of the temperature sensor on diffraction microstructures made of polymer with silver nanoparticles is demonstrated in the range from 20 °C to 95 °C by testing it with a probe radiation of a He – Ne laser. (paper)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2017

Characterization of the Surface of Silver Ion-Implanted Silicon by Optical Reflectance

The optical reflection of the surface of silicon implanted with Ag{sup +} ions at low energy of 30 keV in a wide dosage range of 5.0·10{sup 14}–1.5·10{sup 17} ion/cm{sup 2} was studied in parallel with electron microscopy observation of the samples. It was found that with increasing ion dose of irradiation, the reflection intensity in the UV range of the Si spectrum decreases monotonically due to amorphization and macrostructuring of Si near-surface layer. In the long-wavelength region of the reflection spectra, a selective band with a maximum near 830 nm is recorded due to the plasmon resonance of ion-synthesized Ag nanoparticles.

77 NANOSCIENCE AND NANOTECHNOLOGY↗