SURFACE STRUCTURES AND GROWTH MODES FOR Cu ON Si(100), (110) AND (111) SURFACES DEPENDING ON Cu SEGREGATION BY HEAT TREATMENT

1996 ◽  
Vol 03 (03) ◽  
pp. 1377-1385 ◽  
Author(s):  
T. IKEDA ◽  
T. WATANABE ◽  
H. ITOH ◽  
T. ICHINOKAWA
Keyword(s):  
Heat Treatment ◽  
Substrate Surface ◽  
Surface Structures ◽  
Structure Changes ◽  
Growth Modes ◽  
Reconstructed Surfaces ◽  
Different Temperatures ◽  
Increasing Temperature ◽  
Cohesive Energies ◽  
Large Diffusion

Cu has a large diffusion coefficient in Si, like Ni, and hence the deposited Cu atoms on the Si clean surfaces diffuse into the bulk with increasing temperature and segregate to the surface by quenching. Thus, the surface reconstructed structure changes by heat treatment depending on the surface Cu concentration induced by heat treatment. Moreover, the quantity of Cu segregation decreases with increasing annealing time, because the diffused Cu atoms are trapped to islands on the surface while annealing. The quantity of diffusing Cu atoms into the bulk and the desorption temperatures of Cu from the reconstructed surfaces depend on the crystallographic orientations of the substrate surface. Different cohesive energies of the surface superstructures and different temperatures of the Cu segregation depending on surface orientations are discussed based on the structures on Cu–Si layers formed on the Si (100), (110) and (111) surfaces.

Rem and Rheed Studies of Pb Adsorption on Si(111)

1992 ◽  
Vol 280 ◽  
Author(s):  
Yasumasa Tanishiro ◽  
Masahiko Fukuyamaand ◽  
Katsumichi Yagi
Keyword(s):  
Phase Transition ◽  
Heat Treatment ◽  
Phase Diagram ◽  
Surface Structures ◽  
Structure Changes ◽  
Incommensurate Structures

ABSTRACTStructure changes of Si(111)-Pb surfaces due to deposition and heat treatment are studied by REM-RHEED. Surface structures observed are summarized as a phase diagram. Formation of an incommensurate layer(α) and a phase transition between incommensurate structures of α and α' is described.

Study the Effect of Heat Treatment and Pressure on some the Optical Properties of the Pure PVA Nano Polymer

2021 ◽  
Vol 900 ◽  
pp. 16-25
Author(s):  
Tabarak Mohammed Awad ◽  
May A.S. Mohammed
Keyword(s):  
Heat Treatment ◽  
Dielectric Constant ◽  
Refractive Index ◽  
Optical Properties ◽  
Absorption Coefficient ◽  
Polyvinyl Alcohol ◽  
Complex Dielectric Constant ◽  
Different Temperatures ◽  
German Origin ◽  
Increasing Temperature

In this study, some optical properties were studied of the pure vinyl polyvinyl alcohol (PVA) nanopolymer (German origin). Under the influence of different temperatures and pressures of PVA. Where 25 samples were prepared for the purpose of conducting the research. Which studied the study of these samples was done by recording the absorbance and transmittance spectra of the wavelengths (200-900) nm. From them, absorbance, transmittance, reflectivity, absorption coefficient, refractive index, extinction coefficient, complex dielectric constant were calculated. At different temperatures (25,40, 80, 120, 160)°C. And with different pressures within the range (7.5,8,8.5,9,9.5) MPa. The results are that the permeability of the polymer (PVA) at different temperatures for each pressure decreases with increasing temperature, and that all other calculated optical properties increase with increasing temperature.

Rem and Rheed Studies of Pb Adsorption on Si(111)

1992 ◽  
Vol 295 ◽  
Author(s):  
Yasumasa Tanishiro ◽  
Masahiko Fukuyama ◽  
Katsumichi Yagi
Keyword(s):  
Phase Transition ◽  
Heat Treatment ◽  
Phase Diagram ◽  
Surface Structures ◽  
Structure Changes ◽  
Incommensurate Structures

AbstractStructure changes of Si(111)-Pb surfaces due to deposition and heat treatment are studied by REM-RHEED. Surface structures observed are summarized as a phase diagram. Formation of an incommensurate layer(α) and a phase transition between incommensurate structures of α and α′ is described.

Heat Treatment Influence on the Corrosion Resistance of a Cu-Al-Fe-Mn Bronze

2018 ◽  
Vol 69 (5) ◽  
pp. 1055-1059 ◽  
Author(s):  
Mariana Ciurdas ◽  
Ioana Arina Gherghescu ◽  
Sorin Ciuca ◽  
Alina Daniela Necsulescu ◽  
Cosmin Cotrut ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Structural Changes ◽  
Heating Temperature ◽  
Galvanic Corrosion ◽  
Cooling Water ◽  
Open Circuit ◽  
Water Quenching ◽  
Heat Treated ◽  
Different Temperatures

Aluminium bronzes are exhibiting good corrosion resistance in saline environments combined with high mechanical properties. Their corrosion resistance is obviously confered by the alloy chemical composition, but it can also be improved by heat treatment structural changes. In the present paper, five Cu-Al-Fe-Mn bronze samples were subjected to annealing heat treatments with furnace cooling, water quenching and water quenching followed by tempering at three different temperatures: 200, 400 and 550�C. The heating temperature on annealing and quenching was 900�C. The structure of the heat treated samples was studied by optical and scanning electron microscopy. Subsequently, the five samples were submitted to corrosion tests. The best resistance to galvanic corrosion was showed by the quenched sample, but it can be said that all samples are characterized by close values of open-circuit potentials and corrosion potentials. Concerning the susceptibility to other types of corrosion (selective leaching, pitting, crevice corrosion), the best corrosion resistant structure consists of a solid solution, g2 and k compounds, corresponding to the quenched and 550�C tempered sample.

scholarly journals A Comparative Electrochemical and Morphological Investigation on the Behavior of NiCr and CoCr Dental Alloys at Various Temperatures

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 256
Author(s):  
Florentina Golgovici ◽  
Mariana Prodana ◽  
Florentina Gina Ionascu ◽  
Ioana Demetrescu
Keyword(s):  
Low Temperatures ◽  
Artificial Saliva ◽  
Electrochemical Stability ◽  
Morphological Investigation ◽  
Dental Alloys ◽  
Ion Release ◽  
Icp Ms ◽  
Different Temperatures ◽  
Good Concordance ◽  
Increasing Temperature

The purpose of our study is to compare the behavior of two reprocessed dental alloys (NiCr and CoCr) at different temperatures considering the idea that food and drinks in the oral cavity create various compositions at different pH levels; the novelty is the investigation of temperature effect on corrosion parameters and ion release of dental alloys. Electrochemical stability was studied together with morphology, elemental composition and ions release determination. The results obtained are in good concordance: electrochemistry studies reveal that the corrosion rate is increasing by increasing the temperature. From SEM coupled with EDS, the oxide film formed on the surface of the alloys is stable at low temperatures and a trend to break after 310K. ICP-MS results evidence that in accordance with increasing temperature, the quantities of ions released from the alloys immersed in artificial saliva also increase, though they still remain small, less than 20 ppm.

scholarly journals Simulation of FDSOI-ISFET with Tunable Sensitivity by Temperature and Dual-Gate Structure

Electronics ◽  
2021 ◽  
Vol 10 (13) ◽  
pp. 1585
Author(s):  
Hanbin Wang ◽  
Jinshun Bi ◽  
Mengxin Liu ◽  
Tingting Han
Keyword(s):  
Gate Voltage ◽  
Computer Aided Design ◽  
Silicon On Insulator ◽  
Fully Depleted ◽  
Gate Structure ◽  
Different Temperatures ◽  
Dual Gate ◽  
Sensitivity Changes ◽  
Increasing Temperature ◽  
Aided Design

This work investigates the different sensitivities of an ion-sensitive field-effect transistor (ISFET) based on fully depleted silicon-on-insulator (FDSOI). Using computer-aided design (TCAD) tools, the sensitivity of a single-gate FDSOI based ISFET (FDSOI-ISFET) at different temperatures and the effects of the planar dual-gate structure on the sensitivity are determined. It is found that the sensitivity increases linearly with increasing temperature, reaching 890 mV/pH at 75 °C. By using a dual-gate structure and adjusting the control gate voltage, the sensitivity can be reduced from 750 mV/pH at 0 V control gate voltage to 540 mV/pH at 1 V control gate voltage. The above sensitivity changes are produced because the Nernst limit changes with temperature or the electric field generated by different control gate voltages causes changes in the carrier movement. It is proved that a single FDSOI-ISFET can have adjustable sensitivity by adjusting the operating temperature or the control gate voltage of the dual-gate device.

scholarly journals Correlation and prediction of solubility of hydrogen in alkenes and its dissolution properties

2021 ◽  
Author(s):  
Mohammad Jamali ◽  
Amir Abbas Izadpanah ◽  
Masoud Mofarahi
Keyword(s):  
Equation Of State ◽  
Binary Interaction ◽  
Absolute Deviation ◽  
Dissolution Properties ◽  
Different Temperatures ◽  
Binary Interaction Parameters ◽  
Delta G ◽  
Hoff Equation ◽  
Increasing Temperature ◽  
Total Average

AbstractIn this work, solubility of hydrogen in some alkenes was investigated at different temperatures and pressures. Solubility values were calculated using the Peng–Robinson equation of state. Binary interaction parameters were calculated using fitting the equation of state on experimental data, Group contribution method and Moysan correlations and total average absolute deviation for these methods was 3.90, 17.60 and 13.62, respectively. Because hydrogen solubility in Alkenes is low, Henry’s law for these solutions were investigated, too. Results of calculation showed with increasing temperature, Henry’s constant was decreased. The temperature dependency of Henry’s constants of hydrogen in ethylene and propylene was higher than to other alkenes. In addition, using Van’t Hoff equation, the thermodynamic parameters for dissolution of hydrogen in various alkenes were calculated. Results indicated that the dissolution of hydrogen was spontaneous and endothermic. The total average of dissolution enthalpy ($${\Delta H}^{^\circ }$$ Δ H ∘ ) and Gibbs free energy ($${\Delta G}^{^\circ }$$ Δ G ∘ ) for these systems was 3.867 kJ/mol and 6.361 kJ/mol, respectively. But dissolution of hydrogen in almost of alkenes was not an entropy-driven process.

Temperature Dependence of Hole Impact Ionization Coefficient in 4H-SiC Photodiodes

2009 ◽  
Vol 615-617 ◽  
pp. 311-314 ◽  
Author(s):  
W.S. Loh ◽  
J.P.R. David ◽  
B.K. Ng ◽  
Stanislav I. Soloviev ◽  
Peter M. Sandvik ◽  
...  
Keyword(s):  
Phonon Scattering ◽  
Impact Ionization ◽  
Positive Temperature Coefficient ◽  
Positive Temperature ◽  
Different Temperatures ◽  
Ionization Coefficients ◽  
Increasing Temperature ◽  
The Impact ◽  
Good Agreement ◽  
Ionization Rates

Hole initiated multiplication characteristics of 4H-SiC Separate Absorption and Multiplication Avalanche Photodiodes (SAM-APDs) with a n- multiplication layer of 2.7 µm were obtained using 325nm excitation at temperatures ranging from 300 to 450K. The breakdown voltages increased by 200mV/K over the investigated temperature range, which indicates a positive temperature coefficient. Local ionization coefficients, including the extracted temperature dependencies, were derived in the form of the Chynoweth expression and were used to predict the hole multiplication characteristics at different temperatures. Good agreement was obtained between the measured and the modeled multiplication using these ionization coefficients. The impact ionization coefficients decreased with increasing temperature, corresponding to an increase in breakdown voltage. This result agrees well with the multiplication characteristics and can be attributed to phonon scattering enhanced carrier cooling which has suppressed the ionization process at high temperatures. Hence, a much higher electric field is required to achieve the same ionization rates.

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