Morphological Transition of Epitaxial Rhodium (111)

1995 ◽  
Vol 399 ◽  
Author(s):  
Frank Tsui ◽  
Joanne Wellman ◽  
Ctirad Uher ◽  
Roy Clarke
Keyword(s):  
Surface Roughness ◽  
Film Thickness ◽  
Nucleation And Growth ◽  
Layer Growth ◽  
Morphological Transition ◽  
Layer By Layer ◽  
Surface Features ◽  
General Pathway ◽  
Nucleation Size ◽  
Persistent Layer

ABSTRACTWe report a global morphological transition in the nucleation and growth of epitaxial Rh (111). The transition occurs near 600 K, about 1/4 of the Rh melting temperature, and is signaled by a change in the shape of the surface features from fingered to compact. The transition appears to be related to a change in the critical nucleation size from 1 to 2 atoms. On both sides of the transition, there lies a regime of persistent layer-by-layer growth indicated by a minimum in surface roughness and by the presence of RHEED oscillations. The general surface features exhibit well defined length scales that are not self-affine, and as growth proceeds they increase in size following a power-law dependence on film thickness with a temperature-independent exponent of 0.33 ± 0.03. The results suggest a general pathway to the layer-by-layer growth of close-packed metals.

scholarly journals Modeling the Layer-by-Layer Growth of HKUST-1 Metal-Organic Framework Thin Films

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1631
Author(s):  
Qiang Zhang ◽  
Yohanes Pramudya ◽  
Wolfgang Wenzel ◽  
Christof Wöll
Keyword(s):  
Thin Films ◽  
Surface Roughness ◽  
Deposition Rate ◽  
Layer Growth ◽  
Coarse Grained ◽  
Structural Defects ◽  
Effect Of Temperature ◽  
Layer By Layer ◽  
Reactant Concentration ◽  
Metal Organic

Metal organic frameworks have emerged as an important new class of materials with many applications, such as sensing, gas separation, drug delivery. In many cases, their performance is limited by structural defects, including vacancies and domain boundaries. In the case of MOF thin films, surface roughness can also have a pronounced influence on MOF-based device properties. Presently, there is little systematic knowledge about optimal growth conditions with regard to optimal morphologies for specific applications. In this work, we simulate the layer-by-layer (LbL) growth of the HKUST-1 MOF as a function of temperature and reactant concentration using a coarse-grained model that permits detailed insights into the growth mechanism. This model helps to understand the morphological features of HKUST-1 grown under different conditions and can be used to predict and optimize the temperature for the purpose of controlling the crystal quality and yield. It was found that reactant concentration affects the mass deposition rate, while its effect on the crystallinity of the generated HKUST-1 film is less pronounced. In addition, the effect of temperature on the surface roughness of the film can be divided into three regimes. Temperatures in the range from 10 to 129 °C allow better control of surface roughness and film thickness, while film growth in the range of 129 to 182 °C is characterized by a lower mass deposition rate per cycle and rougher surfaces. Finally, for T larger than 182 °C, the film grows slower, but in a smooth fashion. Furthermore, the potential effect of temperature on the crystallinity of LbL-grown HKUST-1 was quantified. To obtain high crystallinity, the operating temperature should preferably not exceed 57 °C, with an optimum around 28 °C, which agrees with experimental observations.

A benchtop capillary flow layer-by-layer (CF-LbL) platform for rapid assembly and screening of biodegradable nanolayered films

Lab on a Chip ◽  
2016 ◽  
Vol 16 (23) ◽  
pp. 4601-4611 ◽  
Author(s):  
Ziye Dong ◽  
Ling Tang ◽  
Caroline C. Ahrens ◽  
Zhenya Ding ◽  
Vi Cao ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Film Thickness ◽  
Capillary Flow ◽  
Layer By Layer

We report a benchtop platform to systematically study film thickness, surface roughness, biocompatibility and degradation of a series of biodegradable nanolayered films.

Detection of Interfaces States Correlated with Layer-by-Layer Oxidation on Si(100)

1999 ◽  
Vol 592 ◽  
Author(s):  
T. Hattori ◽  
H. Nohira ◽  
Y Teramoto ◽  
N. Watanabe
Keyword(s):  
Surface Roughness ◽  
Oxide Film ◽  
Film Thickness ◽  
Interface State ◽  
State Density ◽  
Layer By Layer ◽  
Oxide Film Thickness ◽  
Maximum Value ◽  
State Densities ◽  
Atomically Flat

ABSTRACTThe interface state densities near the midgap were measured with the progress of oxidation of atomically flat Si(100) surface. It was found that the interface state distribution in Si bandgap changes periodically with the progress of oxidation. Namely, the interface-state density near the midgap of Si exhibits drastic decrease at oxide film thickness where the surface roughness of oxide film takes its minimum value, while that does not exhibit decrease at the oxide film thickness where the surface roughness takes its maximum value. In order to minimize interface state densities the oxide film thickness should be precisely controlled to within an accuracy of 0.02 nm.

In-Situ Stm Studies on the Electrodeposition of Ultrathin Nickel Films

1996 ◽  
Vol 451 ◽  
Author(s):  
O. M. Magnussen ◽  
F. A. Möller ◽  
A. Lachenwitzer ◽  
R. J. Behm
Keyword(s):  
Specific Surface ◽  
Single Crystals ◽  
Complex Potential ◽  
Growth Process ◽  
Nucleation And Growth ◽  
Layer Growth ◽  
Layer By Layer ◽  
Surface Sites ◽  
In Situ Stm

ABSTRACTAn in-situ STM study of the initial stages of Ni electrodeposition on Au and Cu single-crystals is presented. On reconstructed Au(111) a complex, potential-dependent nucleation and growth process is found, involving selective Ni island formation at specific surface sites and growth of two types (compact and needle-like) of Ni monolayer islands. At higher coverages (1 ML ≤ θ ≤ 5 ML) an almost perfect layer-by-layer growth of a metallic Ni(111)-film was observed. Considerably rougher films were found on Au(100) and Cu(100).

The influence of the deposition energy on thin film formation: Co on Si(111)

2003 ◽  
Vol 792 ◽  
Author(s):  
Koen Vanormelingen ◽  
Bart Degroote ◽  
André Vantomme
Keyword(s):  
Thin Film ◽  
Surface Roughness ◽  
Substrate Surface ◽  
Layer Growth ◽  
Low Energy ◽  
Layer By Layer ◽  
Ion Energy ◽  
Deposition Energy ◽  
Ion Deposition

ABSTRACTThe deposition of a thin film on a substrate surface can be achieved with a wide variety of techniques. Deposition using low energy ion beams is not a common technique, but it yields promising features, due to the hyperthermal nature of the deposited ions. With low energy ion deposition, it is possible to grow films with good characteristics at significantly lower temperatures compared to thermal deposition. The quality of these films critically depends on the energy of the impinging ions. We investigated the influence of the energy on the surface morphology for the deposition of Co onto Si(111). The roughness of this surface decreases significantly when the ion energy is increased, until it reaches a minimum at 25 eV. When the ion energy is further increased, the surface roughness increases again. This behavior can be explained by taking into account the interplay between the beneficial and detrimental effects due to the ion energy. Beneficial effects such as enhanced mobility and improved layer-by-layer growth cause a decrease in surface roughness when the deposition energy is increased from thermal to 25 eV. For energies above that value, undesirable effects such as defect creation and pileup dominate, leading to an increase in surface roughness. This study shows that low energy ion deposition can be used to improve the surface quality of a thin film by choosing the optimal deposition energy.

scholarly journals Growth mode study of MgCl2 on Au foil and Si (111) 7x7, under Ultra High Vacuum by XPS

2011 ◽  
Vol 1 (1) ◽  
pp. 13-16
Author(s):  
S. Karakalos
Keyword(s):  
Surface Roughness ◽  
Photoelectron Spectroscopy ◽  
Magnesium Chloride ◽  
High Vacuum ◽  
Layer Growth ◽  
Ultra High Vacuum ◽  
Growth Mode ◽  
Layer By Layer ◽  
X Ray ◽  
Reconstructed Surface

The growth mode of MgCl2 on Au foil and Si (111) 7x7 reconstructed surface under UHV conditions, was investigated by X-ray Photoelectron Spectroscopy (XPS). Magnesium chloride grows with the Frank-van der Merve, (FM) growth mode on the Au foil. On Si surface there is evidence for the layer by layer growth of MgCl2 but leaving uncovered silicon areas at the first steps of deposition due to the Si (111)7x7 surface roughness.

Persistent layer-by-layer growth for pulsed-laser homoepitaxy of $(000\bar 1)$ ZnO

2012 ◽  
Vol 6 (11) ◽  
pp. 433-435 ◽  
Author(s):  
Jan Zippel ◽  
Michael Lorenz ◽  
Gabriele Benndorf ◽  
Marius Grundmann
Keyword(s):  
Pulsed Laser ◽  
Layer Growth ◽  
Layer By Layer ◽  
Persistent Layer

A new method for quantifying the blocking of coated paperboard

TAPPI Journal ◽  
2010 ◽  
Vol 9 (5) ◽  
pp. 29-35 ◽  
Author(s):  
PAULINE SKILLINGTON ◽  
YOLANDE R. SCHOEMAN ◽  
VALESKA CLOETE ◽  
PATRICE C. HARTMANN
Keyword(s):  
Surface Roughness ◽  
Fatty Acid ◽  
Surface Energy ◽  
Film Thickness ◽  
External Factors ◽  
Additive Concentration ◽  
Pressure Surface ◽  
Fatty Acid Amides ◽  
Coated Surfaces ◽  
Definite Period

Blocking is undesired adhesion between two surfaces when subjected to pressure and temperature constraints. Blocking between two coated paperboards in contact with each other may be caused by inter-diffusion, adsorption, or electrostatic forces occurring between the respective coating surfaces. These interactions are influenced by factors such as the temperature, pressure, surface roughness, and surface energy. Blocking potentially can be reduced by adjusting these factors, or by using antiblocking additives such as talc, amorphous silica, fatty acid amides, or polymeric waxes. We developed a method of quantifying blocking using a rheometer. Coated surfaces were put in contact with each other with controlled pressure and temperature for a definite period. We then measured the work necessary to pull the two surfaces apart. This was a reproducible way to accurately quantify blocking. The method was applied to determine the effect external factors have on the blocking tendency of coated paperboards, i.e., antiblocking additive concentration, film thickness, temperature, and humidity.

Oblique-incidence Reflectivity Difference (OI-RD) and Leed Studies of Adsorption and Growth of Xe on Nb(110)

2003 ◽  
Vol 780 ◽  
Author(s):  
P. Thomas ◽  
E. Nabighian ◽  
M.C. Bartelt ◽  
C.Y. Fong ◽  
X.D. Zhu
Keyword(s):  
Transition Layer ◽  
Layer Growth ◽  
Flow Mode ◽  
Layer By Layer ◽  
Zeroth Order ◽  
Step Flow ◽  
Low Energy Electron Diffraction ◽  
Oriented Film ◽  
Low Energy Electron

AbstractWe studied adsorption, growth and desorption of Xe on Nb(110) using an in-situ obliqueincidence reflectivity difference (OI-RD) technique and low energy electron diffraction (LEED) from 32 K to 100 K. The results show that Xe grows a (111)-oriented film after a transition layer is formed on Nb(110). The transition layer consists of three layers. The first two layers are disordered with Xe-Xe separation significantly larger than the bulk value. The third monolayer forms a close packed (111) structure on top of the tensile-strained double layer and serves as a template for subsequent homoepitaxy. The adsorption of the first and the second layers are zeroth order with sticking coefficient close to one. Growth of the Xe(111) film on the transition layer proceeds in a step flow mode from 54K to 40K. At 40K, an incomplete layer-by-layer growth is observed while below 35K the growth proceeds in a multilayer mode.

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