Atomic-Scale Mapping of Layer-by-Layer Hydrogen Etching and Passivation of SiC(0001) Substrates

2016 ◽  
Vol 120 (19) ◽  
pp. 10361-10367 ◽  
Author(s):  
Stefan Glass ◽  
Felix Reis ◽  
Maximilian Bauernfeind ◽  
Julian Aulbach ◽  
Markus R. Scholz ◽  
...  
Keyword(s):  
Atomic Scale ◽  
Layer By Layer ◽  
Hydrogen Etching

The Plasma Deposition of Semiconductor Multilater Structures

1989 ◽  
Vol 165 ◽  
Author(s):  
Masataka Hirose ◽  
Seiichi Miyazaki
Keyword(s):  
Thin Film ◽  
Silicon Nitride ◽  
Amorphous Silicon ◽  
Plasma Deposition ◽  
Substrate Surface ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Atomic Scale ◽  
Layer By Layer ◽  
X Ray

AbstractThe early stages of thin film deposition from the rf glow discharge of SiH4 or SiH4 + NH3 have been studied by analysing the structure of silicon based multiiayers consisting of hydrogenated amorphous silicon (a-Si:H, 10 – 200 A thick) and stoichiometric silicon nitride (a-Si3N4:H, 25 – 250 A) alternating layers. The x-ray diffraction, its rocking curve and x-ray interference of the multilayers have shown that the amorphous silicon/silicon nitride interface is atomically abrupt and the surfaces of the respective layers are atomically flat regardless of substrate materials. This indicates that the precursors impinging onto a substrate from the gas phase homogeneously cover the growing surface and the layer by layer growth proceeds on atomic scale. In the plasma deposition of the covalently bonded semiconductors and insulators, the island formation on a substrate surface at the beginning of the thin film growth is very unlikely.

scholarly journals Precise Layer Control of MoTe2 by Ozone Treatment

Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 756 ◽  
Author(s):  
Qiyuan Wang ◽  
Jing Chen ◽  
Youwei Zhang ◽  
Laigui Hu ◽  
Ran Liu ◽  
...  
Keyword(s):  
Transition Metal Dichalcogenides ◽  
Atomic Scale ◽  
Ozone Treatment ◽  
Layer By Layer ◽  
Precise Control ◽  
Metal Dichalcogenides ◽  
Multiple Cycles ◽  
P Type ◽  
Device Properties ◽  
Layer Control

Transition metal dichalcogenides (TMDCs) demonstrate great potential in numerous applications. However, these applications require a precise control of layer thickness at the atomic scale. In this work, we present an in-situ study of the self-limiting oxidation process in MoTe2 by ozone (O3) treatment. A precise layer-by-layer control of MoTe2 flakes can be achieved via multiple cycles of oxidation and wet etching. The thinned MoTe2 flakes exhibit comparable optical properties and film quality to the pristine exfoliated ones. Besides, an additional p-type doping is observed after O3 oxidation. Such a p-doping effect converts the device properties of MoTe2 from electron-dominated to hole-dominated ambipolar characteristics.

Preparation of (111)-Oriented Pt Electrode Films with Quasi-Monocrystal Properties on MgO/TiN Buffered Si(100) by PLD

2007 ◽  
Vol 280-283 ◽  
pp. 823-826 ◽  
Author(s):  
Tong Lai Chen ◽  
Xiao Min Li
Keyword(s):  
High Energy ◽  
Layer Growth ◽  
Atomic Scale ◽  
Layer By Layer ◽  
X Ray Diffraction ◽  
Pt Electrode ◽  
Force Microscopy ◽  
Atomic Force

Atomic-scale smooth Pt electrode films have been deposited on MgO/TiN buffered Si (100) by the pulsed laser deposition (PLD) technique. The whole growth process of the multilayer films was monitored by using in-situ reflection high energy electron diffraction (RHEED) apparatus. The Pt/MgO/TiN/Si(100) stacked structure was also characterized by X-ray diffraction (XRD), atomic force microscopy (AFM) and scanning electron microscopy (SEM). The HREED observations show that the growth mode of the Pt electrode film is 2D layer-by-layer growth. It is found that the (111)-oriented Pt electrode film has a crystallinity comparable to that of monocrystals. The achievement of the quasi-single-crystal Pt electrode film with an atomic-scale smooth surface is ascribed to the improved crystalline quality of the MgO film.

Elastic fields of interacting point defects within an ultra-thin fcc film bonded to a rigid substrate

2013 ◽  
Vol 3 (4) ◽  
Author(s):  
Hossein Shodja ◽  
Maryam Tabatabaei ◽  
Alireza Ostadhossein ◽  
Ladan Pahlevani
Keyword(s):  
Point Defects ◽  
Binary Systems ◽  
Nearest Neighbor ◽  
Atomic Scale ◽  
Surface Shape ◽  
Atomic Interaction ◽  
Interatomic Potentials ◽  
Layer By Layer ◽  
Face Centered Cubic ◽  
Elastic Fields

AbstractCertain physical and mechanical phenomena within ultra-thin face-centered cubic (fcc) films containing common types of interacting point defects are addressed. An atomic-scale lattice statics in conjunction with many-body interatomic potentials suitable for binary systems is conducted to analyze the effects of the depth on the: (1) formation energy and layer-by-layer displacements due to the presence of vacancy-octahedral self-interstitial atom (OSIA) ensemble, and (2) elastic fields as well as the free surface shape in the case of vacancy-dopant interaction. Moreover, the effects of the inter-defect spacing for various depths are also examined. To ensure reasonable accuracy and numerical convergence, the atomic interaction up to the second-nearest neighbor is considered.

scholarly journals Defect-driven selective metal oxidation at atomic scale

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Qi Zhu ◽  
Zhiliang Pan ◽  
Zhiyu Zhao ◽  
Guang Cao ◽  
Langli Luo ◽  
...  
Keyword(s):  
Reaction Dynamics ◽  
Binding Energies ◽  
Crystal Defects ◽  
Oxidation Catalysis ◽  
Atomic Scale ◽  
Layer By Layer ◽  
Oxygen Binding ◽  
Planar Defects ◽  
Transmission Electron ◽  
Site Selective

AbstractNanoscale materials modified by crystal defects exhibit significantly different behaviours upon chemical reactions such as oxidation, catalysis, lithiation and epitaxial growth. However, unveiling the exact defect-controlled reaction dynamics (e.g. oxidation) at atomic scale remains a challenge for applications. Here, using in situ high-resolution transmission electron microscopy and first-principles calculations, we reveal the dynamics of a general site-selective oxidation behaviour in nanotwinned silver and palladium driven by individual stacking-faults and twin boundaries. The coherent planar defects crossing the surface exhibit the highest oxygen binding energies, leading to preferential nucleation of oxides at these intersections. Planar-fault mediated diffusion of oxygen atoms is shown to catalyse subsequent layer-by-layer inward oxide growth via atomic steps migrating on the oxide-metal interface. These findings provide an atomistic visualization of the complex reaction dynamics controlled by planar defects in metallic nanostructures, which could enable the modification of physiochemical performances in nanomaterials through defect engineering.

Laser MBE for Atomically Defined Ceramic Film Growth

1995 ◽  
Vol 397 ◽  
Author(s):  
H. Koinuma ◽  
M. Kawasaki ◽  
M. Yoshimoto
Keyword(s):  
Film Growth ◽  
Molecular Layer ◽  
High Vacuum ◽  
Layer Growth ◽  
Atomic Scale ◽  
In Situ Monitoring ◽  
Layer By Layer ◽  
Sintered Ceramic ◽  
Infinite Layer ◽  
Laser Mbe

ABSTRACTLaser MBE is a process especially useful for epitaxial layer-by-layer growth of ceramic thin films directly from sintered ceramic targets. By employing high vacuum MBE conditions, the process has a restriction in the controllability of chemical composition, e.g. nonstoi chiometry in oxides and nitrides, as compared with conventional pulsed laser deposition, but instead gains the possibility of in situ monitoring of surface reaction on an atomic scale by RHEED. Ever since our first success in observing RHEED intensity oscillation for CeO2 film growth on Si(l11), we have verified the molecular layer epitaxy by laser MBE for perovskite oxides (SrTiO3, BaTiO3, SrVO3 ,etc) and infinite-layer cuprates MCuO2 (M= Sr, Ba, Ca) on SrTiO3 substrates as well as for oxide and nitride films on Si substrates. Key factors to design the laser MBE system, operation parameters, and recent experimental results are presented and discussed.

Atomic Structure and Chemistry of Si/Ge Interfaces Determined by Z-Contrast Stem

1989 ◽  
Vol 159 ◽  
Author(s):  
M. F. Chisholm ◽  
S. J. Pennycook ◽  
D. E. Jesson
Keyword(s):  
Critical Thickness ◽  
Film Formation ◽  
Film Surface ◽  
Atomic Scale ◽  
Layer By Layer ◽  
Si Substrate ◽  
Powerful Approach ◽  
Z Contrast ◽  
Contrast Image ◽  
Misfit Accommodation

ABSTRACTThe technique of Z-contrast STEM provides a fundamentally new and powerful approach to determining the atomic scale structure and chemistry of interfaces. The images produced do not show contrast reversals with defocus or sample thickness, there are no Fresnel fringe effects at interfaces, and no contrast from within an amorphous phase. Such images are unambiguous and intuitively interpretable. In this paper, the technique has been used to directly image subnanometer interdiffusion in ultrathin (SimGen)p superlattices. The Z-contrast image of a (Si8Ge2)p superlattice grown by MBE at 400°C clearly shows significant broadening of the Gerich layer. Also, film formation and misfit accommodation in epitaxial Ge films on (001)Si produced by implantation and oxidation of Si wafers was studied. It was found that the Ge films, which are constrained to grow layer-by-layer, remain completely coherent with the Si substrate to a thickness of 5–6 nm. This is 3 to 6 times thicker than the observed critical thickness for Ge films grown on Si by MBE. It is observed that misfit accommodating dislocations nucleate at the film surface as Shockley partials. The Z-contrast images show these partials can combine to form perfect dislocations whose cores are found to lie entirely in the elastically softer Ge film.

Multiscale Modeling and Analysis of an Ultra-Precision Damage Free Machining Method

2016 ◽  
Vol 07 (01) ◽  
pp. 1640004
Author(s):  
Chaoliang Guan ◽  
Wenqiang Peng
Keyword(s):  
Quartz Glass ◽  
Dynamic Pressure ◽  
Atomic Scale ◽  
Machining Process ◽  
Laser Fusion ◽  
Hydrodynamic Effect ◽  
Layer By Layer ◽  
Elastic Mode ◽  
Ultra Precision ◽  
Laser Induced Damage

Under the condition of high laser flux, laser induced damage of optical element does not occur is the key to success of laser fusion ignition system. US government survey showed that the processing defects caused the laser induced damage threshold (LIDT) to decrease is one of the three major challenges. Cracks and scratches caused by brittle and plastic removal machining are fatal flaws. Using hydrodynamic effect polishing method can obtain damage free surface on quartz glass. The material removal mechanism of this typical ultra-precision machining process was modeled in multiscale. In atomic scale, chemical modeling illustrated the weakening and breaking of chemical bond energy. In particle scale, micro contact modeling given the elastic remove mode boundary of materials. In slurry scale, hydrodynamic flow modeling showed the dynamic pressure and shear stress distribution which are relations with machining effect. Experiment was conducted on a numerically controlled system, and one quartz glass optical component was polished in the elastic mode. Results show that the damages are removed away layer by layer as the removal depth increases due to the high damage free machining ability of the HEP. And the LIDT of sample was greatly improved.

Afm Study of CeO2 Growth on Sapphire as a Buffer Layer for YBa2Cu3O7

1995 ◽  
Vol 401 ◽  
Author(s):  
M. W. Denhoff ◽  
B. F. Mason ◽  
H. T. Tran ◽  
P. D. Grant
Keyword(s):  
Ybco Film ◽  
Three Dimensional ◽  
Layer Growth ◽  
Granular Structure ◽  
Atomic Scale ◽  
Laser Deposition ◽  
Layer By Layer ◽  
Temperature Dependent ◽  
Force Microscopy ◽  
Atomic Force

AbstractThe structure of CeO2 films grown on (1102) sapphire and on YBCO thin films was investigated. The films reported on here were grown by pulsed excimer laser deposition and their surface structure was probed using atomic force microscopy. We found that CeO2 films grown on sapphire were epitaxial with a granular structure which is smooth on an atomic scale. We see evidence of a surface reconstruction on a very smooth CeO2 (100) oriented surface. At higher growth temperatures, three dimensional islands begin to form. When a CeO2 film is grown on top of a YBCO film, the growth mode is two dimensional. The steps in this layer by layer growth are a surprisingly large 2 nm. This is about equal to 4 times the CeO2 lattice constant. This step height appears to be temperature dependent.

Direct atomic-scale observation of layer-by-layer oxide growth during magnesium oxidation

2014 ◽  
Vol 104 (14) ◽  
pp. 141906 ◽  
Author(s):  
He Zheng ◽  
Shujing Wu ◽  
Huaping Sheng ◽  
Chun Liu ◽  
Yu Liu ◽  
...  
Keyword(s):  
Atomic Scale ◽  
Oxide Growth ◽  
Layer By Layer ◽  
Magnesium Oxidation
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