scholarly journals Electronic structure of thermally oxidized tungsten

2021 ◽  
Vol 2103 (1) ◽  
pp. 012234
Author(s):  
S N Timoshnev ◽  
P A Dementev ◽  
E V Dementeva ◽  
M N Lapushkin ◽  
D A Smirnov
Keyword(s):  
Electronic Structure ◽  
Thermal Oxidation ◽  
Valence Band ◽  
Oxidation State ◽  
Oxygen Pressure ◽  
Organic Molecules ◽  
Surface Region ◽  
Tungsten Oxides ◽  
Near Surface ◽  
Tungsten Foil

Abstract The electronic structure of thermally oxidized tungsten used as an emitter in thermal ionization of organic molecules is studied. Tungsten foil was thermally oxidized at oxygen pressure 1 Torr and temperature 950 K. The photoemission spectra from the valence band and O 2s and W 4f core levels are studied under synchrotron excitation with the photon energies 100 ÷ 600 eV. It is shown that thermal oxidation of tungsten leads to the formation in the W near-surface region various tungsten oxides with an oxidation state from 6+ to 4+. In this case, mainly tungsten oxides with an oxidation state of 6+ are formed on the surface, the proportion of which gradually decreases with distance from the surface with an increase in tungsten oxides with an oxidation state of 4+.

Heteroepitaxial Growth Of ZnO Films BY PLD

1997 ◽  
Vol 474 ◽  
Author(s):  
R. D. Vispute ◽  
V. Talyansky ◽  
Z. Trajanovic ◽  
S. Choopun ◽  
M. Downes ◽  
...  
Keyword(s):  
Oxygen Pressure ◽  
Surface Region ◽  
Optical Quality ◽  
Degree Of Crystallinity ◽  
Zno Films ◽  
Heteroepitaxial Growth ◽  
Near Surface ◽  
Ion Channeling ◽  
Deposition Parameters ◽  
High Degree

ABSTRACTHere we present our recent work on the fabrication of high crystalline and optical quality ZnO films on sapphire (001) by pulsed laser deposition. The influence of deposition parameters such as the substrate temperature, oxygen pressure, laser fluence, and pulse repetition rate on the crystalline quality of ZnO layers has been studied. The Ω-rocking curve FWHM of the (002) peak for the films grown at 750°, oxygen pressure 10−5 Torr was 0.17°. The XRD-Ф scans studies revealed that the films were epitaxial with a 30° rotation of the unit cell with respect to the sapphire to achieve a low energy configuration for epitaxial growth. The high degree of crystallinity was confirmed by ion channeling technique providing a minimum Rutherford backscattering yield of 2–3% in the near surface region (-2000Å). The atomic force microscopy revealed smooth hexagonal faceting of the films. The optical absorption edge measured by UV-Visible spectroscopy was sharp at 383 nm. Excellent crystalline properties of these epi-ZnO/sapphire heterostractures are thus promising for III-V nitride heteroepitaxy.

Variations in the electronic structure of the silicon near-surface region during implantation of phosphorus and boron ions

2007 ◽  
Vol 52 (8) ◽  
pp. 898-900 ◽  
Author(s):  
M. T. Normuradov ◽  
A. K. Tashatov ◽  
A. S. Rysbaev ◽  
Zh. B. Khuzhaniyazov ◽  
Yu. Yu. Yuldashev ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Surface Region ◽  
Near Surface ◽  
Boron Ions

scholarly journals Электролюминесценция слоев Ta-=SUB=-2-=/SUB=-O-=SUB=-5-=/SUB=-, полученных методом молекулярного наслаивания

2020 ◽  
Vol 128 (2) ◽  
pp. 224
Author(s):  
А.П. Барабан ◽  
В.А. Дмитриев ◽  
В.Е. Дрозд ◽  
Ю.В. Петров ◽  
В.А. Прокофьев
Keyword(s):  
Electronic Structure ◽  
Spectral Region ◽  
Spectral Distribution ◽  
Luminescence Band ◽  
Surface Region ◽  
Atomic Layer ◽  
Molecular Layering ◽  
Near Surface ◽  
Layer Deposition ◽  
Ta2o5 Layer

Abstract. The work shows the possibility of using electroluminescence to study the structures of Si-Ta2O5 and Si-SiO2-Ta2O5 and to obtain the information about the electronic structure of the Ta2O5 layer and the properties of the SiO2-Ta2O5 boundary. A model of the electronic structure of the Ta2O5 layer obtained by molecular layering (atomic layer deposition) is proposed to explain the type of spectral distribution of luminescence regardless of the method of its excitation. It is shown that the formation of a Ta2O5 layer on the surface of thermally oxidized silicon is accompanied by transformation of the near-surface region of SiO2 and quenching of the luminescence band in the spectral region of 650 nm.

DEPTH-RESOLVED SOFT X-RAY EMISSION SPECTROSCOPY OF Si-BASED MATERIALS

2002 ◽  
Vol 09 (01) ◽  
pp. 461-467 ◽  
Author(s):  
A. V. ZIMINA ◽  
A. S. SHULAKOV ◽  
S. EISEBITT ◽  
W. EBERHARDT
Keyword(s):  
Electronic Structure ◽  
Depth Resolution ◽  
Surface Region ◽  
Primary Electron ◽  
Depth Information ◽  
Near Surface ◽  
X Ray ◽  
Chemical Phase ◽  
Information Depth ◽  
Postimplantation Annealing

We discuss a soft X-ray emission (SXE) valence band (VB) spectroscopy method for the study of the electronic structure and chemical phase composition of solids in a near-surface region with depth resolution. The depth information is obtained by variation of the energy of the incident electron beam used to excite the SXE spectra. As the information depth can be varied from about 1 nm to 1 μm in silicon, this method is suitable for the investigation of materials of modern micro- and nanoelectronics. VB → core level (Si 2p or Al 2p) transitions in Si-based materials are used to demonstrate the technique. It was found that the contribution of the signal from the near-surface region (< 1.5 nm) can be substantial (up to 50%) when the primary electron energy does not exceed the Si L 2,3 threshold by more than 150 eV. The technique is applied to Al impurities in a Si matrix, produced by ion implantation. The electronic structure at the Al sites and depth distribution of the Al impurity change markedly after postimplantation annealing. The observed electronic structure after annealing is in agreement with electronic structure calculations for substitutional Al impurities in a crystalline Si lattice.

Specific features of the electronic structure of fluorinated multiwalled carbon nanotubes in the near-surface region

2009 ◽  
Vol 51 (9) ◽  
pp. 1961-1971 ◽  
Author(s):  
M. M. Brzhezinskaya ◽  
N. A. Vinogradov ◽  
V. E. Muradyan ◽  
Yu. M. Shul’ga ◽  
R. Püttner ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electronic Structure ◽  
Multiwalled Carbon Nanotubes ◽  
Surface Region ◽  
Multiwalled Carbon ◽  
Near Surface

scholarly journals Электронная структура ультратонкой пленки окисла молибдена

2020 ◽  
Vol 62 (10) ◽  
pp. 1618
Author(s):  
П.А. Дементьев ◽  
Е.В. Иванова ◽  
М.Н. Лапушкин ◽  
Д.А. Смирнов ◽  
С.Н. Тимошнев
Keyword(s):  
Electronic Structure ◽  
Oxide Film ◽  
Energy Range ◽  
Oxide Layer ◽  
Valence Band ◽  
Molybdenum Oxide ◽  
Photon Energy ◽  
Oxygen Pressure ◽  
Photoelectron Spectroscopy ◽  
Ultrahigh Vacuum

The electronic structure of an ultra-thin molybdenum oxide film obtained by oxidation of molybdenum at an oxygen pressure of 1 Torr and the effect of adsorption of sodium atoms Na on its electronic structure are studied by ultra-vacuum photoelectron spectroscopy in ultrahigh vacuum. Photoemission spectra from the valence band and core levels of O 2s, Mo 3d Mo 3p, and Na 1p are studied, upon synchrotron excitation in the photon energy range 80 − 600 eV. It is shown that in the formed oxide film, molybdenum is in two states: Mo6+ and Mo4+. On the surface of the oxide, oxygen is induced both in the composition of the oxides and in hydroxyl. It was shown that MoO3 is formed on the surface, and MoO2 at a distance from the surface. The deposition of Na atoms leads to intercalation of the molybdenum oxide layer.

scholarly journals Электронная структура термически окисленного вольфрама

2021 ◽  
Vol 63 (8) ◽  
pp. 1166
Author(s):  
П.А. Дементьев ◽  
Е.В. Дементьева ◽  
М.Н. Лапушкин ◽  
Д.А. Смирнов ◽  
С.Н. Тимошнев
Keyword(s):  
Electronic Structure ◽  
Energy Range ◽  
Tungsten Oxide ◽  
Oxidation State ◽  
Photoelectron Spectroscopy ◽  
Semiconductor Film ◽  
Clean Surface ◽  
Tungsten Oxides ◽  
In Situ Study

Using the method of photoelectron spectroscopy, an in situ study in ultrahigh vacuum of the electronic structure of a clean surface of tungsten oxidized at an oxygen pressure of 1 Torr and temperature of 1000 K was carried out. The spectra of photoemission from the valence band and core levels O 1s, O 2s, W 4f under synchrotron excitation in the photon energy range 80  600 eV are studied. It was found that a semiconductor film of tungsten oxide is formed, which contains various tungsten oxides with an oxidation state of 6+ to 4+. On the surface, mainly tungsten oxides with an oxidation state of 6+ are formed, the proportion of which gradually decreases with distance from the surface with an increase in tungsten oxides with an oxidation state of 4+.

Preparation of cross-sectional samples for near-surface TEM studies

1987 ◽  
Vol 45 ◽  
pp. 380-381
Author(s):  
R.C. Dickenson ◽  
K.R. Lawless
Keyword(s):  
Standard Sample ◽  
Surface Region ◽  
Specimen Preparation ◽  
Thick Sheet ◽  
Drill Bit ◽  
Sample Holder ◽  
Metal Interface ◽  
Cross Sectional ◽  
Near Surface ◽  
Cold Worked

In thermal oxidation studies, the structure of the oxide-metal interface and the near-surface region is of great importance. A technique has been developed for constructing cross-sectional samples of oxidized aluminum alloys, which reveal these regions. The specimen preparation procedure is as follows: An ultra-sonic drill is used to cut a 3mm diameter disc from a 1.0mm thick sheet of the material. The disc is mounted on a brass block with low-melting wax, and a 1.0mm hole is drilled in the disc using a #60 drill bit. The drill is positioned so that the edge of the hole is tangent to the center of the disc (Fig. 1) . The disc is removed from the mount and cleaned with acetone to remove any traces of wax. To remove the cold-worked layer from the surface of the hole, the disc is placed in a standard sample holder for a Tenupol electropolisher so that the hole is in the center of the area to be polished.

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