scholarly journals Структурные и газочувствительные характеристики тонких полупроводниковых пленок PdO различной толщины при детектировании озона

2021 ◽  
Vol 55 (11) ◽  
pp. 1034
Author(s):  
С.В. Рябцев ◽  
Д.А.А. Гхариб ◽  
С.Ю. Турищев ◽  
Л.А. Обвинцева ◽  
А.В. Шапошник ◽  
...  
Keyword(s):  
High Energy ◽  
Electrical Noise ◽  
Semiconductor Films ◽  
Gas Sensitivity ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Oxidative Annealing ◽  
Oxidation In Air ◽  
Palladium Metal ◽  
Semiconductor Properties

PdO films were obtained by thermal deposition of palladium metal with a thickness of 30 and 90 nm, followed by its oxidation in air at different temperatures. PdO oxide films are characterized by transmission electron microscopy (TEM) and reflection high-energy electron diffraction (RHEED). Data on the semiconductor properties and gas sensitivity to different concentrations of ozone in the air are obtained. The optimal temperature conditions for the oxidation of the films are established, which ensure their uniform phase composition and the absence of electrical noise during the detection of gases. The mechanism of the electrical noise appearance in ultrathin films associated with their fragmentation during oxidative annealing is proposed and justified. The possibility of detecting ozone impurities in the air below the maximum permissible concentration (MPC) by PdO semiconductor films is shown.

Structural and Chemical Properties of MBE Grown Niobium Overlayers on (110) Rutile

1996 ◽  
Vol 441 ◽  
Author(s):  
J. Marien ◽  
T. Wagner ◽  
M. Rühle
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Defect Structure ◽  
Chemical Properties ◽  
High Energy ◽  
Initial Growth ◽  
High Energy Electron ◽  
Transmission Electron ◽  
Different Temperatures ◽  
And Chemical Properties

AbstractThin Nb films were grown by MBE in a UHV chamber at two different temperatures (50°C and 950°C) on the (110) surface of TiO2 (rutile).At a growth temperature of 50°C, reflection high energy electron diffraction (RHEED) revealed epitaxial growth of Nb on rutile: (110)[001] TiO2 ¦¦ (100)[001] Nb. In addition, investigations with Auger electron spectroscopy (AES) revealed that a chemical reaction took place between the Nb overlayer and the TiO2 substrate at the initial growth stage. A 2 nm thick reaction layer at the Nb/TiO2 interface has been identified by means of conventional transmission electron microscopy (CTEM) and high-resolution transmission electron microscopy (HRTEM).At a substrate temperature of 950°C, during growth, the Nb film was oxidized completely, and NbO2 grew epitaxially on TiO2. The structure and the chemical composition of the overlayers have been investigated by RHEED, AES, CTEM and HRTEM. Furthermore, it was determined that the reaction of Nb with TiO2 is governed by the defect structure of the TiO2 and the relative oxygen affinities of Nb and TiO2.

In Situ Annealing Observations of Silicon Cross-Sectional TEM Specimens

1988 ◽  
Vol 46 ◽  
pp. 904-905
Author(s):  
E.M. Fiore ◽  
R.A. Herring
Keyword(s):  
Real Time ◽  
Network Formation ◽  
High Energy ◽  
Video Tape ◽  
Cross Sectional ◽  
Dynamic Events ◽  
Transmission Electron ◽  
Minute Period ◽  
Different Temperatures ◽  
A New Technique

With conventional transmission electron microscopy (TEM), dynamic events are pieced together with micrographs from a multitude of specimens annealed at different temperatures over the range of interest. Real-time imaging of dynamic events in the microscope provides the ability to view the entire anneal temperature span with one specimen. As reported by Parker, cross-sectional TEM can be used to observe real-time kinetic phenomena in silicon. Fiore and Herring later reported a new technique for preparing cross-sectional specimens that are annealable to temperatures as high as 1300°C. Both of these recently developed techniques have been used to observe the amorphous-to-crystalline phase transformation and defect network formation in high-energy ion implanted silicon.Cross-sectional specimens were annealed in a Philips CM 12 transmission electron microscope equipped with a heating holder. The specimens were prepared from [111 ]-oriented silicon wafers implanted with 5.5 Mev Ga ions at a dose of lO15 cm-2. Using a ramp-up temperature from ∽30°C to 1000°C over a 5-minute period, the dynamic events were recorded on 3/4-inch video tape from a TEM TV system.

scholarly journals Modulating Band Gap of Boron Doping in Amorphous Carbon Nano-Film

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1780 ◽  
Author(s):  
Rui Zhu ◽  
Qiang Tao ◽  
Min Lian ◽  
Xiaokang Feng ◽  
Jiayu Liu ◽  
...  
Keyword(s):  
Band Gap ◽  
Amorphous Carbon ◽  
Boron Doping ◽  
High Energy ◽  
Amorphous Semiconductor ◽  
Semiconductor Films ◽  
Experimental Conditions ◽  
Sputtering Power ◽  
Fluxing Agent ◽  
Semiconductor Properties

Amorphous carbon (a-C) films are attracting considerable attention to due their large optical band gap (Eopt) range of 1–4 eV. But the hopping conducting mechanism of boron doping a-C (a-C:B) is still mysterious. To exploring the intrinsic reasons behind the semiconductor properties of a-C:B, in this work, the boron doping a-C (a-C:B) nano-film was prepared, and the growth rate and Eopt changing were analyzed by controlling the different experimental conditions of magnetron sputtering. A rapid deposition rate of 10.55 nm/min was obtained. The Eopt is reduced from 3.19 eV to 2.78 eV by improving the substrate temperature and sputtering power. The proportion of sp2/sp3 increasing was uncovered with narrowing the Eopt. The shrinking Eopt can be attributed to the fact that boron atoms act as a fluxing agent to promote carbon atoms to form sp2 hybridization at low energy. Furthermore, boron atoms can impede the formation of σ bonds in carbon atom sp3 hybridization by forming B–C bonds with high energy, and induce the sp3 hybridization transfer to sp2 hybridization. This work is significant to further study of amorphous semiconductor films.

Microstructural and Magnetotransport (EHE) Properties of Epitaxial τ-MnAl on (100)GaAs Substrates by Pulsed Laser Deposition

1995 ◽  
Vol 403 ◽  
Author(s):  
T. M. Rosier ◽  
Y. He ◽  
N. A. El-Masry
Keyword(s):  
High Energy ◽  
Thin Layers ◽  
Phase Transformation Temperature ◽  
Lattice Matching ◽  
Transmission Electron ◽  
Extraordinary Hall Effect ◽  
Ε Phase ◽  
Different Temperatures ◽  
Hall Effect Measurements ◽  
Deposited Films

AbstractWe report on the crystal quality and magnetotransport properties (EHE) of epitaxial (001) τ-MnA1/GaAs(100) grown by the laser ablation deposition technique. Films (10–30 nm thick) were grown by two methods: (1) ablating a τ-MnAl target, prepared in-house; (2) alternate deposition of ultra thin layers of Mn and Al (˜6 periods) followed by annealing at different temperatures. For both deposition approaches ultrathin coherent epitaxial τ-MnAl films have been grown at temperatures in the range 250–420°C that is below the ε-phase transformation temperature. Reflection high energy electron diffraction (RHEED) and high resolution transmission electron microscopy (HRTEM) were used to characterize the crystalline quality of the deposited films. The Extraordinary Hall Effect measurements (EHE) indicate that the deposited films are perpendicularly magnetized showing coercivity up to 6 kOe at room temperature. The epitaxial growth of thin film ferromagnetic materials on lattice matching semiconductor substrates offers the possibility of integrating magnetic and semiconducting devices.

Incontinuous Grain Growth in Pure Co Nanocrystalline Powders Prepared by Mechanical Attrition

2005 ◽  
Vol 20 (11) ◽  
pp. 3054-3060 ◽  
Author(s):  
Xiaoyan Song ◽  
Jiuxing Zhang ◽  
Keyong Yang
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Grain Growth ◽  
Boundary Migration ◽  
High Energy ◽  
Nanocrystalline Powders ◽  
Polycrystalline Materials ◽  
Transmission Electron ◽  
High Resolution Tem ◽  
Different Temperatures

Highly pure Co nanocrystalline powders were prepared by high-energy ball milling under the condition that all operations on the powders were performed in the glovebox filled with highly purified argon gas. A series of annealing experiments at different temperatures were carried out to investigate grain growth in the milled powders. The as-milled and annealed microstructures were observed and analyzed with transmission electron microscopy (TEM), high-resolution TEM, high-resolution scanning electron microscopy, and x-ray diffraction methods. Characteristics of the incontinuous grain growth in the milled nanocrystalline powders were found. It is considered by the authors that the sharp increase in nanograin size in certain intermediate-temperature region is a result of accelerated grain growth promoted by the stored energy as a supplied driving force, and through a particular dominant mechanism of nanograin rotations in contrast to grain boundary migration in polycrystalline materials.

Recrystallization Characteristics of Amorphous Si

1988 ◽  
Vol 100 ◽  
Author(s):  
Rodney A. Herring ◽  
Eric M. Fiore
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ion Implantation ◽  
Single Crystal ◽  
High Energy ◽  
Formation Mechanisms ◽  
Implantation Energy ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Amorphous Si

ABSTRACTThe microstructure of high-energy (0.5–6.0 MEV) As-ion implanted Si and rapid thermal annnealed (RTA'd) Si has been studied by transmission electron microscopy (TEM). The implantations formed buried amorphous layers that recrystallized during RTA at different temperatures and became either single crystal or polycrystalline depending on their implation energy and fluence. At energies > 2.5 MeV and fluences < 1015 cm−2, recrystallization occurred below 400°C and regowth was single crystal. At an energy of 6 MeV and fluence of 5 × 1015 cm−2 recrystallization occurred above 600°C and regrowth was polycrystalline. When the implantation energy and fluence were reduced to 0.5 MeV and 2 × 1014 cm−2, respectively, recrystallization occurred above 600°C and regrowth was polycrystalline. The above results are explained by both the formation mechanisms of amorphous Si resulting from ion implantation and the structural order of a-Si.

scholarly journals Ozone detection by means of semiconductor gas sensors based on palladium (II) oxide

2021 ◽  
Vol 23 (1) ◽  
Author(s):  
Stanislav V. Ryabtsev ◽  
Dina A. A. Ghareeb ◽  
Alexander A. Sinelnikov ◽  
Sergey Yu. Turishchev ◽  
Lyudmila A. Obvintseva ◽  
...  
Keyword(s):  
Ultrathin Films ◽  
Oxide Films ◽  
High Sensitivity ◽  
High Energy ◽  
Palladium Oxide ◽  
Electrical Noise ◽  
Gas Sensitivity ◽  
Semiconductor Gas Sensors ◽  
Ozone Detection ◽  
Uniform Composition

Thin film semiconductor sensors based on palladium oxide were produced to analyse the concentration of ozone in the air. The palladium oxide films were obtained by means of thermal oxidation of ~ 20-30 nm metal in air at various temperatures. The oxide films were studied using electron microscopy and reflection high-energy electron diffraction. The optical, electrophysical, and gas sensitivity properties of the films were investigated. The study determined the optimal oxidation annealing temperature that ensures the uniform composition of the films and absence of electrical noise affecting the gas detection process. The article explains that electrical noise in ultrathin films is caused by their fragmentation during oxidation annealing. The study demonstrated the high sensitivity of the obtained films to oxide.

Void-Lattice Formation in Natural Fluorite by Electron Irradiation

1976 ◽  
Vol 34 ◽  
pp. 614-615 ◽  
Author(s):  
L.E. Murr
Keyword(s):  
Electron Microscope ◽  
Electron Irradiation ◽  
Heavy Ion ◽  
High Energy ◽  
Stoichiometric Ratio ◽  
Direct Observations ◽  
Transmission Electron ◽  
Anion Vacancies ◽  
Cation And Anion Vacancies ◽  
Lattice Formation

The production of void lattices in metals as a result of displacement damage associated with high energy and heavy ion bombardment is now well documented. More recently, Murr has shown that a void lattice can be developed in natural (colored) fluorites observed in the transmission electron microscope. These were the first observations of a void lattice in an irradiated nonmetal, and the first, direct observations of color-center aggregates. Clinard, et al. have also recently observed a void lattice (described as a high density of aligned "pores") in neutron irradiated Al2O3 and Y2O3. In this latter work, itwas pointed out that in order that a cavity be formed,a near-stoichiometric ratio of cation and anion vacancies must aggregate. It was reasoned that two other alternatives to explain the pores were cation metal colloids and highpressure anion gas bubbles.Evans has proposed that void lattices result from the presence of a pre-existing impurity lattice, and predicted that the formation of a void lattice should restrict swelling in irradiated materials because it represents a state of saturation.

Effects of High-Energy Ions on Synthetic Quartz

1972 ◽  
Vol 30 ◽  
pp. 544-545
Author(s):  
Joseph J. Comer ◽  
Charles Bergeron ◽  
Lester F. Lowe
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Beam ◽  
High Energy ◽  
Transmission Electron ◽  
Kikuchi Lines ◽  
High Energy Ions ◽  
Diffraction Patterns ◽  
Dauphiné Twinning ◽  
Beam Damage

Using a Van De Graaff Accelerator thinned specimens were subjected to bombardment by 3 MeV N+ ions to fluences ranging from 4x1013 to 2x1016 ions/cm2. They were then examined by transmission electron microscopy and reflection electron diffraction using a 100 KV electron beam.At the lowest fluence of 4x1013 ions/cm2 diffraction patterns of the specimens contained Kikuchi lines which appeared somewhat broader and more diffuse than those obtained on unirradiated material. No damage could be detected by transmission electron microscopy in unannealed specimens. However, Dauphiné twinning was particularly pronounced after heating to 665°C for one hour and cooling to room temperature. The twins, seen in Fig. 1, were often less than .25 μm in size, smaller than those formed in unirradiated material and present in greater number. The results are in agreement with earlier observations on the effect of electron beam damage on Dauphiné twinning.

P20 phosphor on polyimide as a large area high-resolution transmission screen for slow scan CCD systems

1995 ◽  
Vol 53 ◽  
pp. 20-21
Author(s):  
C. C. Ahn ◽  
S. Karnes ◽  
M. Lvovsky ◽  
C. M. Garland ◽  
H. A. Atwater ◽  
...  
Keyword(s):  
Mechanical Stability ◽  
High Energy ◽  
Practical Implementation ◽  
Line Pair ◽  
Modulation Transfer ◽  
Large Area ◽  
Ccd Imaging ◽  
Transmission Electron ◽  
The One ◽  
Beam Broadening

The bane of CCD imaging systems for transmission electron microscopy at intermediate and high voltages has been their relatively poor modulation transfer function (MTF), or line pair resolution. The problem originates primarily with the phosphor screen. On the one hand, screens should be thick so that as many incident electrons as possible are converted to photons, yielding a high detective quantum efficiency(DQE). The MTF diminishes as a function of scintillator thickness however, and to some extent as a function of fluorescence within the scintillator substrates. Fan has noted that the use of a thin layer of phosphor beneath a self supporting 2μ, thick Al substrate might provide the most appropriate compromise for high DQE and MTF in transmission electron microcscopes which operate at higher voltages. Monte Carlo simulations of high energy electron trajectories reveal that only little beam broadening occurs within this thickness of Al film. Consequently, the MTF is limited predominantly by broadening within the thin phosphor underlayer. There are difficulties however, in the practical implementation of this design, associated mostly with the mechanical stability of the Al support film.

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