Formation of Atomically Flat Silver Films on GaAs with a "Silver Mean" Quasi Periodicity

Science ◽  
1996 ◽  
Vol 273 (5272) ◽  
pp. 226-228 ◽  
Author(s):  
A. R. Smith ◽  
K.-J. Chao ◽  
Q. Niu ◽  
C.-K. Shih
Keyword(s):  
Silver Films ◽  
Silver Mean ◽  
Atomically Flat

“Preparation of Single Crystalline Gold Films for ED Studies”

1972 ◽  
Vol 30 ◽  
pp. 634-635
Author(s):  
Joseph D. C. Peng
Keyword(s):  
Crystal Morphology ◽  
Diffraction Theory ◽  
Scattering Matrix ◽  
Vacuum Evaporation ◽  
Gold Films ◽  
Matrix Formulation ◽  
Silver Films ◽  
Single Crystalline ◽  
Grating Pattern ◽  
Stacking Disorder

The relative intensities of the ED spots in a cross-grating pattern can be calculated using N-beam electron diffraction theory. The scattering matrix formulation of N-beam ED theory has been previously applied to imperfect microcrystals of gold containing stacking disorder (coherent twinning) in the (111) crystal plane. In the present experiment an effort has been made to grow single-crystalline, defect-free (111) gold films of a uniform and accurately know thickness using vacuum evaporation techniques. These represent stringent conditions to be met experimentally; however, if a meaningful comparison is to be made between theory and experiment, these factors must be carefully controlled. It is well-known that crystal morphology, perfection, and orientation each have pronounced effects on relative intensities in single crystals.The double evaporation method first suggested by Pashley was employed with some modifications. Oriented silver films of a thickness of about 1500Å were first grown by vacuum evaporation on freshly cleaved mica, with the substrate temperature at 285° C during evaporation with the deposition rate at 500-800Å/sec.

Low-energy point-reflection EM

1995 ◽  
Vol 53 ◽  
pp. 610-611
Author(s):  
J. C. H. Spence ◽  
X. Zhang ◽  
J. M. Zuo ◽  
U. Weierstall ◽  
E. Munro ◽  
...  
Keyword(s):  
Low Voltage ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Experimental Point ◽  
Crystalline Substrate ◽  
Point Reflection ◽  
Reflection Geometry ◽  
Optical Analog ◽  
Point Projection ◽  
Atomically Flat

The limited penetration of the low-voltage point-projection microscope (PPM) may be avoided by using the reflection geometry to image clean surfaces in ultra-high vacuum. Figure 1 shows the geometry we are using for experimental point-reflection (PRM) imaging. A nanotip field-emitter at about 100 - 1000 volts is placed above a grounded atomically flat crystalline substrate, which acts as a mirror and anode. Since most of the potential is dropped very close to the tip, trajectories are reasonably straight if the sample is in the far-field of the tip. A resolution of 10 nm is sought initially. The specular divergent RHEED beam then defines a virtual source S' below the surface, resulting in an equivalent arrangement to PPM (or defocused CBED). Shadow images of surface asperities are then expected on the distant detector, out of focus by the tip-to-sample distance. These images can be interpreted as in-line electron holograms and so reconstructed (see X. Zhang et al, these proceedings). Optical analog experiments confirm the absence of foreshortening when the detector is parallel to the surface.

Diffraction from arrays of antiphase boundaries in ordered III-V alloys

1987 ◽  
Vol 45 ◽  
pp. 312-313
Author(s):  
T. S. Kuan
Keyword(s):  
High Surface ◽  
Growth Conditions ◽  
Ternary Alloys ◽  
Local Growth ◽  
Antiphase Boundaries ◽  
Surface Mobility ◽  
Ordered Phases ◽  
Diffraction Patterns ◽  
Atomically Flat ◽  
Degree Of Order

Recent electron diffraction studies have found ordered phases in AlxGa1-xAs, GaAsxSb1-x, and InxGa1-xAs alloy systems, and these ordered phases are likely to be found in many other III-V ternary alloys as well. The presence of ordered phases in these alloys was detected in the diffraction patterns through the appearance of superstructure reflections between the Bragg peaks (Fig. 1). The ordered phase observed in the AlxGa1-xAs and InxGa1-xAs systems is of the CuAu-I type, whereas in GaAsxSb1-x this phase and a chalcopyrite type ordered phase can be present simultaneously. The degree of order in these alloys is strongly dependent on the growth conditions, and during the growth of these alloys, high surface mobility of the depositing species is essential for the onset of ordering. Thus, the growth on atomically flat (110) surfaces usually produces much stronger ordering than the growth on (100) surfaces. The degree of order is also affected by the presence of antiphase boundaries (APBs) in the ordered phase. As shown in Fig. 2(a), a perfectly ordered In0.5Ga0.5As structure grown along the <110> direction consists of alternating InAs and GaAs monolayers, but due to local growth fluctuations, two types of APBs can occur: one involves two consecutive InAs monolayers and the other involves two consecutive GaAs monolayers.

Mercury spreading on silver films: interface characteristics

1998 ◽  
Vol 77 (5) ◽  
pp. 1427-1436
Author(s):  
L. Kaplan, A. Shehter, Y. Lereah, H.Ta
Keyword(s):  
Silver Films ◽  
Interface Characteristics

Quasi-Barrierless Submolecular Motion in Mechanically Interlocked Carbon Nanotubes

2020 ◽  
Author(s):  
Julia Villalva ◽  
Belén Nieto-Ortega ◽  
Manuel Melle-Franco ◽  
Emilio Pérez
Keyword(s):  
Density Functional ◽  
Close Contact ◽  
Tight Binding ◽  
Energetic Cost ◽  
Molecular Fragments ◽  
Activation Barriers ◽  
Flat Surfaces ◽  
Different Types ◽  
Atomically Flat ◽  
Derivatives Of

The motion of molecular fragments in close contact with atomically flat surfaces is still not fully understood. Does a more favourable interaction imply a larger barrier towards motion even if there are no obvious minima? Here, we use mechanically interlocked rotaxane-type derivatives of SWNTs (MINTs) featuring four different types of macrocycles with significantly different affinities for the SWNT thread as models to study this problem. Using molecular dynamics, we find that there is no direct correlation between the interaction energy of the macrocycle with the SWNT and its ability to move along or around it. Density functional tight-binding calculations reveal small (<2.5 Kcal·mol-1) activation barriers, the height of which correlates with the commensurability of the aromatic moieties in the macrocycle with the SWNT. Our results show that macrocycles in MINTs rotate and translate freely around and along SWNTs at room temperature, with an energetic cost lower than the rotation around the C−C bond in ethane.<br>

Preparation of Conductive Silver Films from Electrophoretic Concentrates Stabilized with Sorbitan Monooleate and Sodium Bis(2-Ethylhexyl)Sulfosuccinate in n-Decane

2020 ◽  
Vol 82 (3) ◽  
pp. 295-302
Author(s):  
E. V. Poleeva ◽  
A. T. Arymbaeva ◽  
O. A. Bulavchenko ◽  
P. E. Plyusnin ◽  
M. G. Demidova ◽  
...  
Keyword(s):  
Sorbitan Monooleate ◽  
Silver Films

Optical Properties of Sputtered Silver Granular Films

2005 ◽  
Vol 480-481 ◽  
pp. 287-292 ◽  
Author(s):  
S.E. Paje ◽  
F. Teran ◽  
J.M. Riveiro ◽  
J. Llopis ◽  
M.A. García ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Optical Properties ◽  
Optical Absorption ◽  
Surface Morphology ◽  
Silver Clusters ◽  
Plasmon Excitation ◽  
Granular Films ◽  
Silver Films ◽  
Atomic Force ◽  
Atomic Force Micrographs

In this research we study optical absorption and morphology of silver films prepared with a sputtering method. Silver granular films are obtained on a glass substrate for films with thickness smaller than about 60 Å. Superficial silver clusters of around 100 nm in diameter are clearly seen in the atomic force micrographs. The absorption of these samples are characterized by plasmon excitation in the 450-650 nm spectral range, which differs from the known excitation of silver nanoparticles fabricated by different techniques. The optical absorption of silver granular films depend on sputtering conditions like substrate temperature or deposition rate and correlates with the surface morphology.

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