Activation Energy and Blistering Rate in Hydrogen-implanted Semiconductors

2012 ◽  
Vol 1424 ◽  
Author(s):  
Daniel J. Pyke ◽  
Robert G. Elliman ◽  
Jeffrey C. McCallum
Keyword(s):  
Activation Energy ◽  
Annealing Temperature ◽  
Activation Energies ◽  
Arrhenius Behavior ◽  
Blister Formation ◽  
Temperature Range ◽  
Hydrogen Blister

ABSTRACTHydrogen blister rates in Si (100), Si (111) and Ge (100) substrates are compared as a function of annealing temperature and time, for a range of implant energies and fluences. For each material, the rate of blister formation was found to exhibit Arrhenius behavior and to be characterised by a single activation energy over the temperature range examined. The extracted activation energies were 2.28±0.03 eV, 2.17±0.06 eV and 1.4±0.03 eV for (100) Si; (111) Si and (100) Ge, respectively. These results are compared with reported measurements and discussed in relation to proposed models of hydrogen blistering.

scholarly journals High-Temperature Deformation of Naturally Aged 7010 Aluminum Alloy

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 581
Author(s):  
Abdulhakim A. Almajid
Keyword(s):  
Activation Energy ◽  
Aluminum Alloy ◽  
High Temperature ◽  
Threshold Stress ◽  
Activation Energies ◽  
Temperature Deformation ◽  
High Temperature Range ◽  
Temperature Range ◽  
True Activation Energy ◽  
Two Temperatures

This study is focused on the deformation mechanism and behavior of naturally aged 7010 aluminum alloy at elevated temperatures. The specimens were naturally aged for 60 days to reach a saturated hardness state. High-temperature tensile tests for the naturally aged sample were conducted at different temperatures of 573, 623, 673, and 723 K at various strain rates ranging from 5 × 10−5 to 10−2 s−1. The dependency of stress on the strain rate showed a stress exponent, n, of ~6.5 for the low two temperatures and ~4.5 for the high two temperatures. The apparent activation energies of 290 and 165 kJ/mol are observed at the low, and high-temperature range, respectively. These values of activation energies are greater than those of solute/solvent self-diffusion. The stress exponents, n, and activation energy observed are rather high and this indicates the presence of threshold stress. This behavior occurred as a result of the dislocation interaction with the second phase particles that are existed in the alloy at the testing temperatures. The threshold stress decreases in an exponential manner as temperature increases. The true activation energy was computed by incorporating the threshold stress in the power-law relation between the stress and the strain. The magnitude of the true activation energy, Qt dropped to 234 and 102 kJ/mol at the low and high-temperature range, respectively. These values are close to that of diffusion of Zinc in Aluminum and diffusion of Magnesium in Aluminum, respectively. The Zener–Hollomon parameter for the alloy was developed as a function of effective stress. The data in each region (low and high-temperature region) coalescence in a segment line in each region.

About the Electrical Activation of 1×1020 cm-3 Ion Implanted Al in 4H-SiC at Annealing Temperatures in the Range 1500 - 1950°C

2018 ◽  
Vol 924 ◽  
pp. 333-338 ◽  
Author(s):  
Roberta Nipoti ◽  
Alberto Carnera ◽  
Giovanni Alfieri ◽  
Lukas Kranz
Keyword(s):  
Activation Energy ◽  
Sheet Resistance ◽  
Annealing Time ◽  
Thermal Activation ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Thermal Activation Energy ◽  
Electrical Activation ◽  
Temperature Range ◽  
Annealing Temperatures

The electrical activation of 1×1020cm-3implanted Al in 4H-SiC has been studied in the temperature range 1500 - 1950 °C by the analysis of the sheet resistance of the Al implanted layers, as measured at room temperature. The minimum annealing time for reaching stationary electrical at fixed annealing temperature has been found. The samples with stationary electrical activation have been used to estimate the thermal activation energy for the electrical activation of the implanted Al.

Hydrogen–Water Deuterium Exchange over Graphon Supported Group VIII Noble Metals

1973 ◽  
Vol 51 (24) ◽  
pp. 4031-4037 ◽  
Author(s):  
Norman Henry Sagert ◽  
Rita Mary Louise Pouteau
Keyword(s):  
Activation Energy ◽  
Atomic Number ◽  
Noble Metals ◽  
Activation Energies ◽  
Group Viii ◽  
Surface Exchange ◽  
Hydrogen Water ◽  
Temperature Range ◽  
The Third ◽  
Specific Activities

Specific activities of Group VIII noble metals supported on Graphon have been determined for hydrogen–water deuterium exchange. Metal surface areas, which are required to calculate specific activities, were measured by hydrogen chemisorption, and by reaction of hydrogen with chemisorbed oxygen. For the second triad metals, ruthenium, rhodium, and palladium, and in the temperature range 140 to 225 °C, the variation of activity was Ru < Rh > Pd. For the third triad metals, osmium, iridium, and platinum, the variation of activities was Os < Ir < Pt in the same range of temperature. Apparent activation energies were measured over this temperature range, and orders of reaction with respect to hydrogen and water were measured at 160 °C (200 °C for Pt). From these data, activation energies for the surface exchange reaction were calculated. In the second triad the activation energies decrease slightly with increasing atomic number, but in the third triad they decrease quite markedly with increasing atomic number. A good correlation was obtained between the activation energy for surface exchange and the thermionic work function of the metal. This supports our earlier suggestion that Graphon is able to donate electrons to the metal and thus lower the activation energy for the surface exchange.

Activation Energy for the Post Implantation Annealing of 1019 cm-3 and 1020 cm-3 Ion Implanted Al in 4H SiC

2019 ◽  
Vol 963 ◽  
pp. 416-419
Author(s):  
Roberta Nipoti ◽  
Maria Concetta Canino ◽  
Sergio Sapienza ◽  
Michele Bellettato ◽  
Giovanna Sozzi ◽  
...  
Keyword(s):  
Activation Energy ◽  
Annealing Temperature ◽  
Activation Energies ◽  
Electrical Activation ◽  
Substitutional Site ◽  
Annealing Temperatures ◽  
Implantation Temperature ◽  
Exponential Trend ◽  
Post Implantation ◽  
Ion Implanted

The activation energy for the electrical activation of 1x1019 cm-3 and of 1x1020 cm-3 ion implanted Al in 4H-SiC has been estimated. Ion implantation temperature and dose rate were in the range 430-500°C and around 1011 cm2s-1, respectively. Post implantation annealing temperatures varied between 1500 °C and 1950 °C. The annealing time per each annealing temperature was sufficiently long that the sheet resistance of the implanted layer could be equal to the stationary value at the applied annealing temperature. The Arrhenius plots of the room temperature sheet resistances with respect to the post implantation annealing temperatures featured an exponential trend for both the implanted Al concentrations. The activation energies of these plots are the activation energy for placing an implanted Al atom in a substitutional site, i.e. the electrical activation energy. Activation energies around 1 eV, equal within errors for the two implanted Al concentrations, were found.

scholarly journals Effect of CaO on catalytic combustion of semi-coke

2021 ◽  
Vol 10 (1) ◽  
pp. 011-020
Author(s):  
Luyao Kou ◽  
Junjing Tang ◽  
Tu Hu ◽  
Baocheng Zhou ◽  
Li Yang
Keyword(s):  
Activation Energy ◽  
Apparent Activation Energy ◽  
Combustion Rate ◽  
Activation Energies ◽  
Combustion Reaction ◽  
Tg Analysis ◽  
Conversion Rates ◽  
Apparent Activation Energies ◽  
Ozawa Integral Method ◽  
Addition Amount

Abstract Generally, adding a certain amount of an additive to pulverized coal can promote its combustion performance. In this paper, the effect of CaO on the combustion characteristics and kinetic behavior of semi-coke was studied by thermogravimetric (TG) analysis. The results show that adding proper amount of CaO can reduce the ignition temperature of semi-coke and increase the combustion rate of semi-coke; with the increase in CaO content, the combustion rate of semi-coke increases first and then decreases, and the results of TG analysis showed that optimal addition amount of CaO is 2 wt%. The apparent activation energy of CaO with different addition amounts of CaO was calculated by Coats–Redfern integration method. The apparent activation energy of semi-coke in the combustion reaction increases first and then decreases with the increase in CaO addition. The apparent activation energies of different samples at different conversion rates were calculated by Flynn–Wall–Ozawa integral method. It was found that the apparent activation energies of semi-coke during combustion reaction decreased with the increase in conversion.

scholarly journals The Effect of α-Al(MnCr)Si Dispersoids on Activation Energy and Workability of Al-Mg-Si-Cu Alloys during Hot Deformation

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Xiaoguo Wang ◽  
Jian Qin ◽  
Hiromi Nagaumi ◽  
Ruirui Wu ◽  
Qiushu Li
Keyword(s):  
Activation Energy ◽  
Aluminum Alloys ◽  
Constitutive Equation ◽  
Hot Deformation ◽  
Flow Instability ◽  
Void Formation ◽  
Activation Energies ◽  
Compression Tests ◽  
Softening Mechanism ◽  
Dynamic Softening

The hot deformation behaviors of homogenized direct-chill (DC) casting 6061 aluminum alloys and Mn/Cr-containing aluminum alloys denoted as WQ1 were studied systematically by uniaxial compression tests at various deformation temperatures and strain rates. Hot deformation behavior of WQ1 alloy was remarkably changed compared to that of 6061 alloy with the presence of α-Al(MnCr)Si dispersoids. The hyperbolic-sine constitutive equation was employed to determine the materials constants and activation energies of both studied alloys. The evolution of the activation energies of two alloys was investigated on a revised Sellars’ constitutive equation. The processing maps and activation energy maps of both alloys were also constructed to reveal deformation stable domains and optimize deformation parameters, respectively. Under the influence of α dispersoids, WQ1 alloy presented a higher activation energy, around 40 kJ/mol greater than 6061 alloy’s at the same deformation conditions. Dynamic recrystallization (DRX) is main dynamic softening mechanism in safe processing domain of 6061 alloy, while dynamic recovery (DRV) was main dynamic softening mechanism in WQ1 alloy due to pinning effect of α-Al(MnCr)Si dispersoids. α dispersoids can not only resist DRX but also increase power required for deformation of WQ1 alloy. The microstructure analysis revealed that the flow instability was attributed to the void formation and intermetallic cracking during hot deformation of both alloys.

Observation of Rheed Intensity Oscillations During PbSe/CaF2/Si(111) MBE

1996 ◽  
Vol 441 ◽  
Author(s):  
W. K. Liu ◽  
X. M. Fang ◽  
P. J. McCann ◽  
M. B. Santos
Keyword(s):  
Activation Energy ◽  
Melting Point ◽  
Substrate Temperature ◽  
High Melting ◽  
Arrhenius Behavior ◽  
High Activation ◽  
High Melting Point ◽  
Mbe Growth ◽  
Sublimation Energy ◽  
Initial Nucleation

AbstractRHEED intensity oscillations observed during MBE growth of CaF2 on Si(111) and PbSe on CaF2/Si(111) are presented. The effects of substrate temperature and initial nucleation procedure are investigated. Strong temporal oscillations of the specular beam intensity are found to be most readily observed at temperatures below 200°C for both CaF2 and PbSe. Growth rates measured as a function of cell temperatures exhibit Arrhenius behavior with activation energies of 5.0 eV and 1.93 eV for CaF2 and PbSe, respectively. The relatively high activation energy obtained for CaF2 is consistent with the high melting point and sublimation energy of ionic fluorides.

New experiments on the relationship between light-induced defects and photoconductivity degradation

2001 ◽  
Vol 664 ◽  
Author(s):  
Stephan Heck ◽  
Howard M. Branz
Keyword(s):  
Activation Energy ◽  
Defect Density ◽  
Activation Energies ◽  
Dangling Bond ◽  
Fast Recovery ◽  
Slow Recovery ◽  
Degradation Model ◽  
Induced Defects ◽  
The Relationship ◽  
Hydrogenated Amorphous

ABSTRACTWe report experimental results that help settle apparent inconsistencies in earlier work on photoconductivity and light-induced defects in hydrogenated amorphous silicon (a-Si:H) and point toward a new understanding of this subject. After observing that light-induced photoconductivity degradation anneals out at much lower T than the light-induced increase in deep defect density, Han and Fritzsche[1] suggested that two kinds of defects are created during illumination of a-Si:H. In this view, one kind of defect degrades the photoconductivity and the other increases defect sub-bandgap optical absorption. However, the light-induced degradation model of Stutzmann et al.[2] assumes that photoconductivity is inversely proportional to the dangling-bond defect density. We observe two kinds of defects that are distinguished by their annealing activation energies, but because their densities remain in strict linear proportion during their creation, the two kinds of defects cannot be completely independent.In our measurements of photoconductivity and defect absorption (constant photocurrent method) during 25°C light soaking and during a series of isochronal anneals between 25 < T < 190°C, we find that the absorption measured with E ≤1.1 eV, first increases during annealing, then exhibits the usual absorption decrease found for deeper defects. The maximum in this absorption at E ≤1.1eV occurs simultaneously with a transition from fast to slow recovery of photoconductivity. The absorption for E ≤1.1eV shows two distinct annealing activation energies: the signal rises with about 0.87 eV and falls with about 1.15 eV. The 0.87 eV activation energy roughly equals the activation energy for the dominant, fast, recovery of photoconductivity. The 1.15 eV activation energy roughly equals the single activation energy for annealing of the light-induced dangling bond absorption.

Thermooxidative Aging Studies on Silicone Rubber and Lifetime Prediction

2013 ◽  
Vol 777 ◽  
pp. 11-14
Author(s):  
You Shan Wang ◽  
Sha Sha Jiang ◽  
Yu Peng Liu
Keyword(s):  
Silicone Rubber ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Activation Energies ◽  
Lifetime Prediction ◽  
Arrhenius Behavior ◽  
Compression Set ◽  
Degradation Processes ◽  
Aging Studies ◽  
Significant Compression

Silicone rubber have been aged in air while under 25% compression at temperature up to 250°C. These studies examined the compression set of silicone rubber at accelerated (elevated) temperatures and were then used to make predictions about compression set at room temperature. The data obtained could be amenable to timetemperature superposition and Arrhenius treatment. The results suggest the presence of two degradation processes with activation energies of 71.6 kJ mol-1 (for temperatures above 165 °C) and 26.08 kJ mol-1 (for temperatures below 165 °C). Based on the extrapolation of the non-Arrhenius behavior, it was estimated that significant compression set loss would occur after around 67 years at 25 °C.

scholarly journals SYNTHESIS AND ELECTRICAL CONDUCTIVITY OF SOLID SOLUTIONS OF THE SYSTEM RbF-PbF2-SnF2

2019 ◽  
Vol 85 (5) ◽  
pp. 60-68
Author(s):  
Yuliay Pogorenko ◽  
Anatoliy Omel’chuk ◽  
Roman Pshenichny ◽  
Anton Nagornyi
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Temperature Dependence ◽  
Solid Solutions ◽  
Basic Structure ◽  
Elementary Cell ◽  
Initial Structure ◽  
Fluoride Ions ◽  
Temperature Range ◽  
Order Of Magnitude

In the system RbF–PbF2–SnF2 are formed solid solutions of the heterovalent substitution RbxPb0,86‑xSn1,14F4-x (0 < x ≤ 0,2) with structure of β–PbSnF4. At x > 0,2 on the X-ray diffractograms, in addition to the basic structure, additional peaks are recorded that do not correspond to the reflexes of the individual fluorides and can indicate the formation of a mixture of solid solutions of different composition. For single-phase solid solutions, the calculated parameters of the crystal lattice are satisfactorily described by the Vegard rule. The introduction of ions of Rb+ into the initial structure leads to an increase in the parameter a of the elementary cell from 5.967 for x = 0 to 5.970 for x = 0.20. The replacement of a part of leads ions to rubium ions an increase in electrical conductivity compared with β–PbSnF4 and Pb0.86Sn1.14F4. Insignificant substitution (up to 3.0 mol%) of ions Pb2+ at Rb+ at T<500 K per order of magnitude reduces the conductivity of the samples obtained, while the nature of its temperature dependence is similar to the temperature dependence of the conductivity of the sample β-PbSnF4. By replacing 5 mol. % of ions with Pb2+ on Rb+, the fluoride ion conductivity at T> 450 K is higher than the conductivity of the initial sample Pb0,86Sn1,14F4 and at temperatures below 450 K by an order of magnitude smaller. With further increase in the content of RbF the electrical conductivity of the samples increases throughout the temperature range, reaching the maximum values at x≥0.15 (σ573 = 0.34–0.41 S/cm, Ea = 0.16 eV and σ373 = (5.34–8.16)•10-2 S/cm, Ea = 0.48–0.51 eV, respectively). In the general case, the replacement of a part of the ions of Pb2+ with Rb+ to an increase in the electrical conductivity of the samples throughout the temperature range. The activation energy of conductivity with an increase in the content of RbF in the low-temperature region in the general case increases, and at temperatures above 400 K is inversely proportional decreasing. The nature of the dependence of the activation energy on the concentration of the heterovalent substituent and its value indicate that the conductivity of the samples obtained increases with an increase in the vacancies of fluoride ions in the structure of the solid solutions.

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