scholarly journals Calculation of the optical transmittance in cadmium oxide by considering oxygen plasma

2018 ◽  
Vol 39 (1) ◽  
pp. 65-74
Author(s):  
M. A. Grado-Caffaro ◽  
M. Grado-Caffaro
Keyword(s):  
Experimental Data ◽  
Partial Pressure ◽  
Cadmium Oxide ◽  
Detailed Comparison ◽  
Optical Transmittance ◽  
Deposition Process ◽  
Visible Range ◽  
Experimental Measurements ◽  
Partial Pressure Of Oxygen ◽  
Physical Quantities

Abstract By considering the partial pressure of oxygen in the deposition process of cadmium oxide, we calculate the maximum transmittance of cadmium oxide in the visible range, which is achieved at the so-called optimum partial pressure of oxygen, this value of pressure being a key figure of merit. Our formulation agrees with experimental measurements and is consistent with the so-called plasma-optical effect. At this point, an exhaustive evaluation of previous experimental data is performed by doing a detailed comparison among the results from different authors and by performing numerical estimations (including estimations from experimental data) of relevant physical quantities. In fact, a comprehensive discussion relative to comparison between experimental measurements and our theoretical results is presented.

Theoretical analysis on the sensitivity to partial pressure of oxygen of the band gap shift in CdO thin films

2016 ◽  
Vol 30 (31) ◽  
pp. 1650371 ◽  
Author(s):  
M. A. Grado-Caffaro ◽  
M. Grado-Caffaro
Keyword(s):  
Thin Films ◽  
Partial Pressure ◽  
Band Gap ◽  
Cadmium Oxide ◽  
Visible Region ◽  
Visible Range ◽  
Partial Pressure Of Oxygen ◽  
Sensitivity Functions ◽  
Suitable Parameter ◽  
Cdo Thin Films

With the aim of providing an analytical approach (not accurate numerical results), for the first time, the sensitivity to the partial pressure of oxygen of the shift in the energy band gap experienced by cadmium-oxide thin films is evaluated for the visible region by introducing a suitable parameter. The sensitivity to the above pressure of the spatial carrier density is determined and compared with the sensitivity relative to the band gap shift. The gradient of the CdO carrier concentration as a function of the partial pressure of oxygen appears in the expressions for the two above sensitivity functions but the goal of this paper is not computing numerically this gradient so only qualitative estimations are done. In relation to the above results, the kinetics relative to the formation of CdO thin films are investigated. In addition, the sensitivity to the pressure in question of the corresponding optical-absorption shift in the visible range is calculated.

On the sensitivity to partial pressure of oxygen of the mobility in cadmium oxide

2015 ◽  
Vol 29 (32) ◽  
pp. 1550206 ◽  
Author(s):  
M. A. Grado-Caffaro ◽  
M. Grado-Caffaro
Keyword(s):  
Partial Pressure ◽  
Cadmium Oxide ◽  
Mean Free Path ◽  
Deposition Process ◽  
Drift Mobility ◽  
Electron Drift ◽  
Partial Pressure Of Oxygen ◽  
Theoretical Formulation ◽  
Activated Reactive Evaporation ◽  
Electron Drift Mobility

The partial pressure of oxygen during the deposition process of cadmium oxide is a crucial quantity whose influence on the electrical and optical properties of this material is really very significant (consider, for example, the experimental technique known as activated reactive evaporation). In fact, this paper is a theoretical formulation to evaluate the sensitivity changes of the aforementioned pressure of the electron drift-mobility and velocity in CdO. Indeed, as we will see later, given that the electron relaxation time depends upon the oxygen partial pressure, then the electron drift-mobility, mean free path and velocity also depend on this pressure. Relevant calculations involving the above physical quantities are carried out.

Leaching Behaviour of Metals from a Sphalerite Concentrate in Sulfuric Acid-Oxygen System

2011 ◽  
Vol 201-203 ◽  
pp. 1725-1731
Author(s):  
Cun Xiong Li ◽  
Chang Wei ◽  
Hong Sheng Xu ◽  
Ji Qiang Liao ◽  
Zhi Gan Deng ◽  
...  
Keyword(s):  
Experimental Data ◽  
Particle Size ◽  
Sulfuric Acid ◽  
Partial Pressure ◽  
Elemental Sulphur ◽  
Partial Pressure Of Oxygen ◽  
Mineralogical Analysis ◽  
Oxygen System ◽  
Copper Indium ◽  
Leaching Behaviour

Leaching behaviors of zinc, copper, indium and iron from a sphalerite concentrate in sulfuric acid-oxygen system has been investigated in the present paper. Various parameters were studied including particle size, concentration of sulfuric acid, partial pressure of oxygen, leaching temperature, and leaching time. The experimental data indicated that under the typical plant conditions employed up to 99% zinc , 85% copper and 90% indium extraction were achieved. The mineralogical analysis of the residue showed that the main minerals are elemental sulphur, unreacted pyrite and quartz, the amount of sulphide sulphur oxidized to sulfur during leaching is 81%. This process provides an effective way for the extraction of zinc, copper and indium from sphalerite concentrate.

scholarly journals Optical and Structural Characterization of Cd-Free Buffer Layers Fabricated by Chemical Bath Deposition

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 897
Author(s):  
William Vallejo ◽  
Carlos Diaz-Uribe ◽  
Cesar Quiñones
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Chemical Bath Deposition ◽  
Structural Characterization ◽  
Optical Transmittance ◽  
Deposition Process ◽  
Buffer Layers ◽  
Visible Range ◽  
Electromagnetic Spectrum ◽  
Distribution Diagram

Chemical bath deposition (CBD) is a suitable, inexpensive, and versatile synthesis technique to fabricate different semiconductors under soft conditions. In this study, we deposited Zn(O;OH)S thin films by the CBD method to analyze the effect of the number of thin film layers on structural and optical properties of buffer layers. Thin films were characterized by X-ray diffraction (XRD) and UV-Vis transmittance measurements. Furthermore, we simulated a species distribution diagram for Zn(O;OH)S film generation during the deposition process. The optical results showed that the number of layers determined the optical transmittance of buffer layers, and that the transmittance reduced from 90% (with one layer) to 50% (with four layers) at the visible range of the electromagnetic spectrum. The structural characterization indicated that the coatings were polycrystalline (α-ZnS and β-Zn(OH)2 to four layers). Our results suggest that Zn(O;OH)S thin films could be used as buffer layers to replace CdS thin films as an optical window in thin-film solar cells.

scholarly journals Oxidation of glucose and arabinose mixtures over Au/Al2O3

2020 ◽  
Author(s):  
Sebastian Franz ◽  
Nataliya D. Shcherban ◽  
Irina L. Simakova ◽  
Markus Peurla ◽  
Kari Eränen ◽  
...  
Keyword(s):  
Experimental Data ◽  
Kinetic Model ◽  
Partial Pressure ◽  
Catalytic Oxidation ◽  
Batch Reactor ◽  
Oxidation Reactions ◽  
Partial Pressure Of Oxygen ◽  
Oxidation Of Glucose

Abstract Oxidation of a mixture of glucose and arabinose over 1% Au deposited on alumina was investigated in a semi-batch reactor varying pH, temperature and partial pressure of oxygen. Elevation of the latter enhancing the rate induced also losses in selectivity to aldonic acids. A kinetic model representing the catalytic oxidation reactions of arabinose and glucose along with respective isomerization to fructose and ribulose was developed. Calculations based on the model were able to describe experimental data in a reliable way.

NEW RESULTS ON OPTICAL ABSORPTION IN AMORPHOUS CADMIUM OXIDE FOR THE VISIBLE RANGE: A THEORETICAL APPROACH

2004 ◽  
Vol 18 (24) ◽  
pp. 1255-1259 ◽  
Author(s):  
M. A. GRADO-CAFFARO ◽  
M. GRADO-CAFFARO
Keyword(s):  
Experimental Data ◽  
Optical Absorption ◽  
Band Gap ◽  
Density Of States ◽  
Theoretical Approach ◽  
Cadmium Oxide ◽  
Visible Region ◽  
Visible Range ◽  
Phonon Density ◽  
Phonon Density Of States

Optical absorption of amorphous cadmium oxide in the visible region is investigated by considering the band-gap shift experienced by this material. At the same time, influence of oxygen partial pressure is studied so that new results related to absorption in the visible margin are obtained; these results agree well with experimental data. In addition, phonon density of states and its shift due to the band-gap shift are evaluated.

Interaction of H2O, O2 and H2 with Proton Conducting Oxides Based on Lanthanum Scandates

2019 ◽  
pp. 88-100
Author(s):  
A. S. Farlenkov ◽  
N. A. Zhuravlev ◽  
Т. A. Denisova ◽  
М. V. Ananyev
Keyword(s):  
Water Vapor ◽  
Partial Pressure ◽  
Gas Phase ◽  
Molecular Hydrogen ◽  
Proton Magnetic Resonance ◽  
Partial Pressure Of Oxygen ◽  
Proton Conducting ◽  
Conducting Oxides ◽  
Temperature Range ◽  
Apparent Level

The research uses the method of high-temperature thermogravimetric analysis to study the processes of interaction of the gas phase in the temperature range 300–950 °C in the partial pressure ranges of oxygen 8.1–50.7 kPa, water 6.1–24.3 kPa and hydrogen 4.1 kPa with La1–xSrxScO3–α oxides (x = 0; 0.04; 0.09). In the case of an increase in the partial pressure of water vapor at a constant partial pressure of oxygen (or hydrogen) in the gas phase, the apparent level of saturation of protons is shown to increase. An increase in the apparent level of saturation of protons of the sample also occurs with an increase in the partial pressure of oxygen at a constant partial pressure of water vapor in the gas phase. The paper discusses the causes of the observed processes. The research uses the hydrogen isotope exchange method with the equilibration of the isotope composition of the gas phase to study the incorporation of hydrogen into the structure of proton-conducting oxides based on strontium-doped lanthanum scandates. The concentrations of protons and deuterons were determined in the temperature range of 300–800 °C and a hydrogen pressure of 0.2 kPa for La0.91Sr0.09ScO3–α oxide. The paper discusses the role of oxygen vacancies in the process of incorporation of protons and deuterons from the atmosphere of molecular hydrogen into the structure of the proton conducting oxides La1–xSrxScO3–α (x = 0; 0.04; 0.09). The proton magnetic resonance method was used to study the local structure in the temperature range 23–110 °C at a rotation speed of 10 kHz (MAS) for La0.96Sr0.04ScO3–α oxide after thermogravimetric measurements in an atmosphere containing water vapor, and after exposures in molecular hydrogen atmosphere. The existence of proton defects incorporated into the volume of the investigated proton oxide from both the atmosphere containing water and the atmosphere containing molecular hydrogen is unambiguously shown. The paper considers the effect of the contributions of the volume and surface of La0.96Sr0.04ScO3–α oxide on the shape of the proton magnetic resonance spectra.

Diffusion model for deposition of epitaxial GaAs layers prepared by the MOCVD method

1991 ◽  
Vol 56 (10) ◽  
pp. 2020-2029
Author(s):  
Jindřich Leitner ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma ◽  
Rudolf Hladina
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Kinetic Model ◽  
Gas Phase ◽  
Substrate Surface ◽  
Deposition Process ◽  
Hydrogen Atmosphere ◽  
Epitaxial Gaas ◽  
Kinetics Of ◽  
Good Agreement

The authors proposed and treated quantitatively a kinetic model for deposition of epitaxial GaAs layers prepared by reaction of trimethylgallium with arsine in hydrogen atmosphere. The transport of gallium to the surface of the substrate is considered as the controlling process. The influence of the rate of chemical reactions in the gas phase and on the substrate surface on the kinetics of the deposition process is neglected. The calculated dependence of the growth rate of the layers on the conditions of the deposition is in a good agreement with experimental data in the temperature range from 600 to 800°C.

Sign in / Sign up

Export Citation Format

Share Document