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

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.

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Spatially Ordered Matrix of Nanostructured Tin–Tungsten Oxides Nanocomposites Formed by Ionic Layer Deposition for Gas Sensing

Sensors ◽

10.3390/s21124169 ◽

2021 ◽

Vol 21 (12) ◽

pp. 4169

Author(s):

Gennady Gorokh ◽

Natalia Bogomazova ◽

Abdelhafed Taleb ◽

Valery Zhylinski ◽

Timur Galkovsky ◽

...

Keyword(s):

Tungsten Oxide ◽

Gas Sensing ◽

Oxide Films ◽

High Sensitivity ◽

Anodic Alumina ◽

Film Deposition ◽

Silicon Substrates ◽

Layer By Layer ◽

Gas Sensitivity ◽

Nanoporous Anodic Alumina

The process of layer-by-layer ionic deposition of tin-tungsten oxide films on smooth silicon substrates and nanoporous anodic alumina matrices has been studied. To achieve the film deposition, solutions containing cationic SnF2 or SnCl2 and anionic Na2WO4 or (NH4)2O·WO3 precursors have been used. The effect of the solution compositions on the films deposition rates, morphology, composition, and properties was investigated. Possible mechanisms of tin-tungsten oxide films deposition into the pores and on the surface of anodic alumina are discussed. The electro-physical and gas-sensitive properties of nanostructured SnxWyOz films have been investigated. The prepared nanocomposites exhibit stable semiconductor properties characterized by high resistance and low temperature coefficient of electrical resistance of about 1.6 × 10−3 K−1. The sensitivity of the SnxWyOz films to 2 and 10 ppm concentrations of ammonia at 523 K was 0.35 and 1.17, respectively. At concentrations of 1 and 2 ppm of nitrogen dioxide, the sensitivity was 0.48 and 1.4, respectively, at a temperature of 473 K. At the temperature of 573 K, the sensitivity of 1.3 was obtained for 100 ppm of ethanol. The prepared nanostructured tin-tungsten oxide films showed promising gas-sensitivity, which makes them a good candidate for the manufacturing of gas sensors with high sensitivity and low power consumption.

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

Физика и техника полупроводников ◽

10.21883/ftp.2021.11.51557.9684 ◽

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.

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Observation of surface morphology by reflection electron holography

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100154652 ◽

1989 ◽

Vol 47 ◽

pp. 536-537

Author(s):

N. Osakabe ◽

J. Endo ◽

T. Matsuda ◽

A. Tonomura

Keyword(s):

Phase Shift ◽

Surface Morphology ◽

High Sensitivity ◽

High Energy ◽

Path Difference ◽

Transmission Mode ◽

Electron Holography ◽

Dynamical Process ◽

High Vertical Resolution ◽

Amplification Technique

Progress in microscopy such as STM and TEM-TED has revealed surface structures in atomic dimension. REM has been used for the observation of surface dynamical process and surface morphology. Recently developed reflection electron holography, which employes REM optics to measure the phase shift of reflected electron, has been proved to be effective for the observation of surface morphology in high vertical resolution ≃ 0.01 Å.The key to the high sensitivity of the method is best shown by comparing the phase shift generation by surface topography with that in transmission mode. Difference in refractive index between vacuum and material Vo/2E≃10-4 owes the phase shift in transmission mode as shownn Fig. 1( a). While geometrical path difference is created in reflection mode( Fig. 1(b) ), which is measured interferometrically using high energy electron beam of wavelength ≃0.01 Å. Together with the phase amplification technique , the vertivcal resolution is expected to be ≤0.01 Å in an ideal case.

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Epitaxial growth manner and structure of superconducting oxide films

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100173145 ◽

1990 ◽

Vol 48 (4) ◽

pp. 2-3

Author(s):

Yoshichika Bando ◽

Takahito Terashima ◽

Kenji Iijima ◽

Kazunuki Yamamoto ◽

Kazuto Hirata ◽

...

Keyword(s):

Ultrathin Films ◽

Film Surface ◽

High Energy ◽

Epitaxial Films ◽

Layer By Layer ◽

Initial Growth ◽

In Situ Growth ◽

High Quality ◽

Activated Reactive Evaporation

The high quality thin films of high-Tc superconducting oxide are necessary for elucidating the superconducting mechanism and for device application. The recent trend in the preparation of high-Tc films has been toward “in-situ” growth of the superconducting phase at relatively low temperatures. The purpose of “in-situ” growth is to attain surface smoothness suitable for fabricating film devices but also to obtain high quality film. We present the investigation on the initial growth manner of YBCO by in-situ reflective high energy electron diffraction (RHEED) technique and on the structural and superconducting properties of the resulting ultrathin films below 100Å. The epitaxial films have been grown on (100) plane of MgO and SrTiO, heated below 650°C by activated reactive evaporation. The in-situ RHEED observation and the intensity measurement was carried out during deposition of YBCO on the substrate at 650°C. The deposition rate was 0.8Å/s. Fig. 1 shows the RHEED patterns at every stage of deposition of YBCO on MgO(100). All the patterns exhibit the sharp streaks, indicating that the film surface is atomically smooth and the growth manner is layer-by-layer.

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Low-temperature solution processing of palladium/palladium oxide films and their pH sensing performance

Talanta ◽

10.1016/j.talanta.2015.08.062 ◽

2016 ◽

Vol 146 ◽

pp. 517-524 ◽

Cited By ~ 16

Author(s):

Yiheng Qin ◽

Arif U. Alam ◽

Si Pan ◽

Matiar M.R. Howlader ◽

Raja Ghosh ◽

...

Keyword(s):

Low Temperature ◽

Oxide Films ◽

Palladium Oxide ◽

Solution Processing ◽

Ph Sensing ◽

Temperature Solution ◽

Sensing Performance

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High-sensitivity external modulator data link for high-energy particle detector diagnostics

10.1117/12.141720 ◽

1993 ◽

Author(s):

Kent G. McCammon ◽

Mark E. Lowry ◽

Yuan-Hann Chang ◽

Paul J. Parker ◽

Bolek Wyslouch ◽

...

Keyword(s):

High Sensitivity ◽

High Energy ◽

High Energy Particle ◽

Particle Detector ◽

Energy Particle ◽

Data Link

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P1GS.13 - Tungsten Oxide Films with High Sensitivity to Nitric Oxide

10.5162/imcs2018/p1gs.13 ◽

2018 ◽

Author(s):

S. Krutovertsev ◽

A. Tarasova ◽

O. Ivanova ◽

L. Krutovertseva

Keyword(s):

Nitric Oxide ◽

Tungsten Oxide ◽

Oxide Films ◽

High Sensitivity

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Synthesis and Gas Sensitivity of Thin Chromium Oxide Films

Technical Physics Letters ◽

10.1134/s106378502010017x ◽

2020 ◽

Vol 46 (10) ◽

pp. 1028-1031

Author(s):

A. V. Almaev ◽

B. O. Kushnarev ◽

E. V. Chernikov ◽

V. A. Novikov

Keyword(s):

Chromium Oxide ◽

Oxide Films ◽

Gas Sensitivity ◽

Thin Chromium

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CP VIOLATION AND BEAUTY DECAYS — A CASE STUDY OF HIGH IMPACT, HIGH SENSITIVITY AND EVEN HIGH PRECISION PHYSICS

International Journal of Modern Physics A ◽

10.1142/s0217751x00000525 ◽

2000 ◽

Vol 15 (08) ◽

pp. 1079-1156

Author(s):

I. I. BIGI

Keyword(s):

Cp Violation ◽

Degrees Of Freedom ◽

High Energy Physics ◽

Dipole Moments ◽

High Sensitivity ◽

High Energy ◽

New Physics ◽

B Decays ◽

New Paradigm ◽

Parametric Reliability

The narrative of these lectures contains three main threads: (i) CP violation despite having so far been observed only in the decays of neutral kaons has been recognized as a phenomenon of truly fundamental importance. The KM ansatz constitutes the minimal implementation of CP violation: without requiring unknown degrees of freedom it can reproduce the known CP phenomenology in a nontrivial way. (ii) The physics of beauty hadrons — in particular their weak decays — opens a novel window onto fundamental dynamics: they usher in a new quark family (presumably the last one); they allow us to determine fundamental quantities of the Standard Model like the b quark mass and the CKM parameters V(cb), V(ub), V(ts) and V(td); they exhibit speedy or even rapid [Formula: see text] oscillations. (iii) Heavy Quark Expansions allow us to treat B decays with an accuracy that would not have been thought possible a mere decade ago. These three threads are joined together in the following manner: (a) Huge CP asymmetries are predicted in B decays, which represents a decisive test of the KM paradigm for CP violation. (b) Some of these predictions are made with high parametric reliability, which (c) can be translated into numerical precision through the judicious employment of novel theoretical technologies. (d) Beauty decays thus provide us with a rich and promising field to search for New Physics and even study some of its salient features. At the end of it there might quite possibly be a New Paradigm for High Energy Physics. There will be some other threads woven into this tapestry: electric dipole moments, and CP violation in other strange and in charm decays.

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