Low Temperature Si Homoepitaxy: Effects of Impurities on Microstructure

1993 ◽  
Vol 312 ◽  
Author(s):  
D. P. Adamst ◽  
D. J. Eaglesham ◽  
S. M. Yalisove
Keyword(s):  
Surface Roughness ◽  
Low Temperature ◽  
Partial Pressure ◽  
Hydrogen Partial Pressure ◽  
Surface Roughening ◽  
Partial Pressures

AbstractHydrogen is shown to influence the surface roughness during low temperature Si MBE. Small partial pressures (1 × 10-7 Torr) of deuterium, introduced during Si growth at 310°C, are sufficient to increase the surface width to ∼30 Å before breakdown of epitaxy. This work is consistent with previous studies of the dependence of epitaxial thickness on hydrogen partial pressure and supports a model in which surface roughening leads to the breakdown of epitaxy.

scholarly journals A Study On The Fabrication Of Iron Powder From Forging Scale Using Hydrogen

2015 ◽  
Vol 60 (2) ◽  
pp. 1547-1549 ◽  
Author(s):  
S.M. Shin ◽  
D.-W. Lee ◽  
J.-Y. Yun ◽  
CH.-Y. Kang ◽  
J.-P. Wang
Keyword(s):  
Partial Pressure ◽  
Iron Powder ◽  
Metallic Iron ◽  
Hydrogen Partial Pressure ◽  
Hydrogen Gas ◽  
Temperature Reaction ◽  
Reduction Of Iron ◽  
Partial Pressures ◽  
Mean Size ◽  
The Mean

Abstract This study was conducted to investigate the effect of hydrogen content, temperature, reaction time for the reduction of forging scale which is mainly composed of hematite (Fe2O3). All reductive reactions were performed over the temperature range of 700 to 1200°C as well as 0.1 to 1 atm of hydrogen partial pressures. The results showed that the mechanism for the reduction of iron oxides using hydrogen gas was not a simple process, but proceeded in multiple reduction stages thermodynamically. The iron oxide was almost completely reduced to metallic iron powder with 91 wt.% of iron content in the forging scale at 0.1 atm of hydrogen partial pressure. The content of iron was however found to be increased with increasing hydrogen partial pressure from 0.1 to 1 atm with regardless of temperatures. The metallic iron powder was obtained with the mean size of 100 μm and more porous structure was observed.

Some Aspects of the Nonstoichiometric and Thermodynamic Behavior of the YBa2Cu3Oz System

1989 ◽  
Vol 156 ◽  
Author(s):  
M. Tetenbaum ◽  
L. Curtiss ◽  
B. Czech ◽  
B. Tani ◽  
M. Blander
Keyword(s):  
Low Temperature ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Coulometric Titration ◽  
Temperature Data ◽  
Oxygen Stoichiometry ◽  
Miscibility Gap ◽  
Thermodynamic Behavior ◽  
Partial Pressures ◽  
Titration Technique

ABSTRACTThe nonstoichiometric and thermodynamic behavior of the YBa2Cu3Ox system as a function of oxygen partial pressure and temperature is being investigated by means of a coulometric titration technique. The oxygen content of the superconductor can be varied coulometrically by well-defined small amounts and the equilibrium partial pressures determined from the EMF. The oxygen stoichiometry in YBa2Cu3Ox as a function of oxygen partial pressure shows a change of curvature around x = 6.55–6.75 and an inflection around x ≅ 6.65 at temperatures between 400–500°C. These new low temperature data are consistent with the presence of a miscibility gap at lower temperatures, which is similar to that postulated in several theoretical papers.

PLD Growth of CNTs using a Nanostuctured Ni Buffer Layer: Dependence of H2 partial Pressure

2006 ◽  
Vol 951 ◽  
Author(s):  
Maneesh Chandran ◽  
K. Mohan Kant ◽  
N. Rama ◽  
M.S. Ramachandra Rao
Keyword(s):  
Thin Films ◽  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Partial Pressure ◽  
Buffer Layer ◽  
Good Yield ◽  
Near Infrared ◽  
Hydrogen Atmosphere ◽  
Hydrogen Partial Pressure ◽  
Partial Pressures

ABSTRACTThe effect of hydrogen partial pressure on the growth of CNT thin films using on-axis PLD has been studied. Using nickel as buffer layer, carbon nanotubes can be produced with good yield in Hydrogen atmosphere. We have found strong visible-near infrared (NIR) photoluminescence (PL) from carbon nanotube thin films synthesized under various hydrogen partial pressures. The present result shows that bright, narrow PL from CNTs can be obtained without any post growth processing.

The influence of surface roughening and Si{111} facets on low temperature Si homoepitaxy

1996 ◽  
Vol 54 ◽  
pp. 950-951
Author(s):  
O.P Karpenko ◽  
S.M. Yalisove
Keyword(s):  
Phase Transition ◽  
Surface Roughness ◽  
Low Temperature ◽  
Epitaxial Growth ◽  
Amorphous Phase ◽  
Substrate Surface ◽  
Growth Surface ◽  
Surface Roughening ◽  
Arrhenius Relation ◽  
Amorphous Si

Recent research in the area of low temperature (T<450°C) epitaxial growth of semiconductors has revealed a number of interesting phenomena which are not yet fully understood. One suchphenomena is the crystalline to amorphous phase transition which occurs during low temperature Si homoepitaxy. For low temperature Si homoepitaxy, crystalline growdi is limited by a critical epitaxial thickness (hepi), beyond which Si grows as an amorphous phase. It has been established that hepi follows an Arrhenius relation with temperature, is preceded by an increase in surface roughness,and is affected by the presence of impurities and the substrate surface orientation. Although the formation of amorphous Si is not fully understood, several models have been proposed to explain this phenomenon. One of these models suggests that Si amorphization is associated with surface roughening andthe formation of Si{111} facets at the growth surface. According to this model, hepi shoulddecreaseasthe density of Si{111} microfacets on the starting increases.

Effect of CO2 on Anti-Corrosion Property of a Polyurea Coating Modified with Organosilicone

2014 ◽  
Vol 789 ◽  
pp. 466-470
Author(s):  
Qing Hao Shi ◽  
Bing Ying Wang ◽  
Bin Zhao
Keyword(s):  
High Temperature ◽  
Partial Pressure ◽  
Composite Coating ◽  
Corrosion Test ◽  
Electrochemical Impedance ◽  
Failure Process ◽  
Corrosion Property ◽  
Corrosion Mechanism ◽  
Partial Pressures ◽  
High Temperature High Pressure

The corrosion mechanism of organic silicon modified polyurea composite coating under different CO2 partial pressures was studied using high-temperature autoclave, combined with scanning electron microscopy (SEM), adhesion tests and electrochemical impedance spectroscopy (EIS) technology. The experimental results showed that: there was no corrosion product formed on the surface of coating sample after high-temperature high-pressure corrosion test, and with the increasing of CO2 partial pressure, the coating adhesion and impedance values decline increases. Moreover CO2 partial pressure increases accelerated the failure process of polyurea composite coating system.

Submicron surface roughening of aliphatic polyamide 6,6 fabric through low temperature plasma and its effect on interfacial bonding in rubber composite

2017 ◽  
Vol 47 (8) ◽  
pp. 2029-2049 ◽  
Author(s):  
Siddhan Periyasamy ◽  
Krishna Prasad G ◽  
Raja ASM ◽  
Prashant G Patil
Keyword(s):  
Surface Roughness ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Plasma Treatment ◽  
Treatment Time ◽  
Surface Roughening ◽  
Temperature Plasma ◽  
Nylon 6,6 ◽  
Rubber Composite ◽  
Scanning Electron

The present study aims to produce submicron surface roughening of aliphatic polyamide 6,6 (nylon 6,6) fabric using dielectric barrier discharge-based atmospheric low temperature plasma for improving the adhesion bonding with rubber. The plasma treatment was done in the time ranging from 15 s to 300 s. Formation of surface roughness on the fabric due to plasma treatment and the associated chemical changes were studied through high-resolution scanning electron microscope, geometrical surface roughness by Kawabata evaluation system surface tester, contact angle measurements and Fourier transform infrared in Attenuated total reflectance mode. Scanning electron microscope micrographs revealed the presence of submicron roughness on the nylon 6,6 fibre surface with pores of around 100 nm (0.1 µm) for the optimum treatment time of 180 s above which the pore merging effect dominated resulting in the net low surface roughness. Geometrical roughness (SMD) results were also well in agreement with the scanning electron microscope results for the roughening and the optimum effect of the plasma treatment. The control and plasma treated nylon 6,6 samples were used as reinforcements for rubber composite. The peel strength of the rubber composite, which is a measure of interfacial bonding, increased to 150% as the maximum for the optimum plasma treatment time of 180 s. Intense rubber deposits over the 180 s plasma treated samples were observed while only a few deposits of rubber were observed on the control fabric when their interfaces were examined through scanning electron microscope after peeling test.

Recrystallization of Oxygen Contaminated Al Films

1986 ◽  
Vol 71 ◽  
Author(s):  
G.J. Van Der Kolk ◽  
M.J. Verkerk
Keyword(s):  
Grain Size ◽  
Silicon Nitride ◽  
Substrate Temperature ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Relative Increase ◽  
Partial Pressures ◽  
Average Grain Size

AbstractAl was evaporated at oxygen partial pressures, PO2, varying between 10−7 and 10−4 Pa on substrates of silicon nitride. The substrate temperature was varied between 20 °C and 250°C. The films were annealed at temperatures up to 500°C.For Al films deposited at 20°C, it was found that the average grain size decreases with increasing oxygen partial pressure. After annealing recrystallization was observed. The relative increase of grain size was less for higher values of pO2. Annealing gave rise to a broad grain size distribution.For Al films deposited at 250°C, the presence of oxygen caused the growth of rough inhomogeneous films. This inhomogeneous structure remained during annealing.

Sign in / Sign up

Export Citation Format

Share Document