Kinetics of optically-induced crystallization and structure of Agx(As0.48S0.26Se0.26)100-x chalcogenide films.

AbstractThe high density optical and/or thermal, electrical memories based on recording into chalcogenide thin films are currently used in industrial dimension but search for new materials continues due to request of higher recording density and shorter lasers wavelength available. The thin films of amorphous chalcogenides e.g. of Ag-As-S(Se) systems making or ternary use different techniques i.e. optically-induced silver dissolution in the binary As-S or As-S-Se chalcogenides prepared by thermal evaporation or by spin coating techniques were prepared and studied. Ternary Ag-As-S and quarternary Ag-As-S(Se) chalcogenide films were also deposited by direct-pulsed laser deposition. Films with euthectic or stoichiometric compositions were prepared. Optically-induced phase-changes in films, process kinetics and analysis of the structural changes and their potential application are described.

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Formation of Bi2S3 thin films on Au(111) by electrochemical atomic layer epitaxy: kinetics of structural changes in the initial monolayers

Journal of Electroanalytical Chemistry ◽

10.1016/s0022-0728(02)00921-x ◽

2002 ◽

Vol 529 (1) ◽

pp. 34-42 ◽

Cited By ~ 35

Author(s):

Tüba Öznülüer ◽

Ümit Demir

Keyword(s):

Thin Films ◽

Structural Changes ◽

Atomic Layer ◽

Atomic Layer Epitaxy ◽

Electrochemical Atomic Layer Epitaxy ◽

Kinetics Of

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Structural Transitions in Ge2Sb2Te5 Phase Change Memory Thin Films Induced by Nanosecond UV Optical Pulses

Materials ◽

10.3390/ma13092082 ◽

2020 ◽

Vol 13 (9) ◽

pp. 2082

Author(s):

Mario Behrens ◽

Andriy Lotnyk ◽

Hagen Bryja ◽

Jürgen W. Gerlach ◽

Bernd Rauschenbach

Keyword(s):

Thin Films ◽

Phase Transitions ◽

Phase Change ◽

Data Storage ◽

Structural Changes ◽

Phase Change Memory ◽

Phase Changes ◽

Uv Laser ◽

Optical Pulses ◽

Change Memory

Ge-Sb-Te-based phase change memory alloys have recently attracted a lot of attention due to their promising applications in the fields of photonics, non-volatile data storage, and neuromorphic computing. Of particular interest is the understanding of the structural changes and underlying mechanisms induced by short optical pulses. This work reports on structural changes induced by single nanosecond UV laser pulses in amorphous and epitaxial Ge2Sb2Te5 (GST) thin films. The phase changes within the thin films are studied by a combined approach using X-ray diffraction and transmission electron microscopy. The results reveal different phase transitions such as crystalline-to-amorphous phase changes, interface assisted crystallization of the cubic GST phase and structural transformations within crystalline phases. In particular, it is found that crystalline interfaces serve as crystallization templates for epitaxial formation of metastable cubic GST phase upon phase transitions. By varying the laser fluence, GST thin films consisting of multiple phases and different amorphous to crystalline volume ratios can be achieved in this approach, offering a possibility of multilevel data storage and realization of memory devices with very low resistance drift. In addition, this work demonstrates amorphization and crystallization of GST thin films by using only one UV laser with one single pulse duration and one wavelength. Overall, the presented results offer new perspectives on switching pathways in Ge-Sb-Te-based materials and show the potential of epitaxial Ge-Sb-Te thin films for applications in advanced phase change memory concepts.

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Effects of the Si/Al layer thickness on the continuity, crystalline orientation and the growth kinetics of the poly-Si thin films formed by aluminum-induced crystallization

Thin Solid Films ◽

10.1016/j.tsf.2016.08.016 ◽

2016 ◽

Vol 616 ◽

pp. 213-219 ◽

Cited By ~ 11

Author(s):

Sergii Tutashkonko ◽

Noritaka Usami

Keyword(s):

Thin Films ◽

Layer Thickness ◽

Growth Kinetics ◽

Crystalline Orientation ◽

Kinetics Of ◽

Induced Crystallization ◽

Aluminum Induced Crystallization

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Transformations in CrFeCoNiCu High Entropy Alloy Thin Films during In-Situ Annealing in TEM

Coatings ◽

10.3390/coatings10010060 ◽

2020 ◽

Vol 10 (1) ◽

pp. 60 ◽

Cited By ~ 1

Author(s):

Mohamed Arfaoui ◽

György Radnóczi ◽

Viktória Kovács Kis

Keyword(s):

Thin Films ◽

Structural Changes ◽

Diffusion Processes ◽

Intermetallic Phase ◽

High Resolution Electron Microscopy ◽

Phase Changes ◽

High Entropy Alloy ◽

In Situ Tem ◽

High Entropy

In-situ TEM-heating study of the microstructural evolution of CrFeCoNiCu high entropy alloy (HEA) thin films was carried out and morphological and phase changes were recorded. Post annealing investigation of the samples was carried out by high resolution electron microscopy and EDS measurements. The film is structurally and morphologically stable single phase FCC HEA up to 400 °C. At 450 °C the formation of a BCC phase was observed, however, the morphology of the film remained unchanged. This type of transformation is attributed to diffusionless processes (martensitic or massive). From 550 °C fast morphological and structural changes occur, controlled by volume diffusion processes. Fast growing of a new intermetallic phase is observed which contains mainly Cr and has large unit cell due to chemical ordering of components in <100> direction. The surface of the films gets covered with a CrO-type layer, possibly contributing to corrosion resistance of these.

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Photo-induced structural changes in obliquely deposited arsenic-based amorphous chalcogenides: a model for photostructural changes

Philosophical Magazine B ◽

10.1080/014186399257357 ◽

1999 ◽

Vol 79 (2) ◽

pp. 249-256 ◽

Cited By ~ 1

Author(s):

Y. Kuzukawa, Ashtosh Ganjoo, K. Shimak

Keyword(s):

Structural Changes ◽

Amorphous Chalcogenides

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Studies on the Behavior Some Paints in Electro-insulating Fluid Based on Vegetable Esters

Revista de Chimie ◽

10.37358/rc.18.5.6276 ◽

2018 ◽

Vol 69 (5) ◽

pp. 1139-1144

Author(s):

Iosif Lingvay ◽

Adriana Mariana Bors ◽

Livia Carmen Ungureanu ◽

Valerica Stanoi ◽

Traian Rus

Keyword(s):

Structural Changes ◽

Oxidation Processes ◽

High Oleic ◽

Painting Materials ◽

Insulating Paper ◽

Different Types ◽

Mechanism And Kinetics ◽

Kinetics Of ◽

Natural Ester

For the purpose of using three different types of painting materials for the inner protection of the transformer vats, their behavior was studied under actual conditions of operation in the transformer (thermal stress in electro-insulating fluid based on the natural ester in contact with copper for electro-technical use and electro-insulating paper). By comparing determination of the content in furans products (HPLC technique) and gases formed (by gas-chromatography) in the electro-insulating fluid (natural ester with high oleic content) thermally aged at 130 �C to 1000 hours in closed glass vessels, it have been found that the presence the investigated painting materials lead to a change in the mechanism and kinetics of the thermo-oxidation processes. These changes are supported by oxygen dissolved in oil, what leads to decrease both to gases formation CO2, CO, H2, CH4, C2H4 and C2H6) and furans products (5-HMF, 2-FOL, 2 -FAL and 2-ACF). The painting materials investigated during the heat treatment applied did not suffer any remarkable structural changes affecting their functionality in the electro-insulating fluid based on vegetable esters.

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Biofilm Structure – An Important and Neglected Parameter in Waste Water Treatment

Water Science & Technology ◽

10.2166/wst.1989.0283 ◽

1989 ◽

Vol 21 (8-9) ◽

pp. 805-814 ◽

Cited By ~ 15

Author(s):

F. R. Christensen ◽

G. Holm Kristensen ◽

J. la Cour Jansen

Keyword(s):

Wastewater Treatment ◽

Structural Changes ◽

Waste Water Treatment ◽

Experimental Investigations ◽

Biofilm Reactors ◽

Substrate Removal ◽

Treatment Processes ◽

Laboratory Reactor ◽

Biofilm Structure ◽

Kinetics Of

Experimental investigations on the kinetics of wastewater treatment processes in biofilms were performed in a laboratory reactor. Parallel with the kinetic experiments, the influence of the biofilm kinetics on the biofilm structure was studied at macroscopic and microscopic levels. The close interrelationship between biofilm kinetics and structural changes caused by the kinetics is illustrated by several examples. From the study, it is evident that the traditional modelling of wastewater treatment processes in biofilm reactors based on substrate removal kinetics alone will fail in many cases, due to the inevitable changes in the biofilm structure not taken into consideration. Therefore design rules for substrate removal in biofilms used for wastewater treatment must include correlations between the removal kinetics and the structure and development of the biological film.

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