Evolution Of Crystalline Microstructure in GeTe Thin Films for Optical Storage Applications

1994 ◽  
Vol 343 ◽  
Author(s):  
M. Libera
Keyword(s):  
Thin Films ◽  
Phase Change ◽  
Optical Storage ◽  
Microstructural Development ◽  
Multilayered Media ◽  
Time Resolved ◽  
Constant Rate ◽  
Individual Contributions ◽  
The Individual ◽  
Transmission Studies

ABSTRACTThe bit-erase process in phase-change optical storage is based on the amorphous to crystalline transformation. While there has been significant progress developing compositions and multilayered media for phase-change applications, quantitative studies of the crystallization kinetics and microstructural development are generally lacking. This paper describes work quantifying crystallization in GeTe thin films. Microstructural changes during isothermal annealing are measured using in-situ hot-stage optical microscopy. This technique measures the fraction crystallized, the number of crystallites, and crystallite radii as a function of time. These data are sufficient to deconvolute the individual contributions of nucleation and growth. We find an Avrami exponent of ∼4, consistent with time-resolved reflection/transmission studies. This exponent is due to 2-D growth at a constant rate plus transient nucleation. The data are used in a kinetic model to simulate non-isothermal crystallization during focused-laser heating characteristic of the bit-erase process.

scholarly journals Contribution of Drude and Brendel Model Terms to the Dielectric Function; A case of TiO2:Nb Thin Films

2018 ◽  
Vol 1 (1) ◽  
pp. 3-7
Author(s):  
Christopher Mkirema Maghanga ◽  
Maurice M Mwamburi
Keyword(s):  
Thin Films ◽  
Dielectric Function ◽  
Parametric Modeling ◽  
Free Electrons ◽  
As Doping ◽  
Niobium Doped ◽  
Spectrophotometric Data ◽  
Drude Term ◽  
Individual Contributions ◽  
The Individual

Parametric modeling provides a mean of deeper understanding to the properties of materials. Dielectric function is one of the key parameters which can provide information on the dielectric nature of a thin film or bulk materials. It can be obtained by modeling the material using appropriate existing, new or modified models. In our work, we utilized existing Brendel and Drude models to extract the optical constants from spectrophotometric data of fabricated undoped and niobium doped titanium oxide thin films. The individual contributions by the two models were studied to establish influence on the dielectric function. The effect of dopants on their influences was also analyzed. Results indicate a minimal contribution from the Drude term due to the dielectric nature of the undoped films. However as doping levels increase, the rise in the concentration of free electrons favors the use of Drude model.

Thickness-dependent Crystallization Behavior of Phase Change Materials

2008 ◽  
Vol 1072 ◽  
Author(s):  
Simone Raoux ◽  
Jean L. Jordan-Sweet ◽  
Andrew J. Kellock
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Phase Change ◽  
Crystallization Behavior ◽  
Phase Change Materials ◽  
Random Access ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
Future Technology ◽  
Technology Nodes

ABSTRACTWe have investigated the crystallization behavior of phase change materials as a function of their thickness. Thin films of variable thickness between 1 and 50nm of the phase change materials Ge2Sb2Te5 (GST), N-doped GST (N-GST), Ge15Sb85 (GeSb), Sb2Te, and Ag and In doped Sb2Te (AIST) were deposited by magnetron sputtering, and capped in situ by a 10nm thick Al2O3 film to prevent oxidation. The crystallization behavior of the films was studied using time-resolved X-ray diffraction. For each material we observed a constant crystallization temperature Tx that was comparable to bulk values for films thicker than 10 nm, and an increased Tx when the film thickness was reduced below 10 nm. The thinnest films that showed XRD peaks were 2 nm for GST and N-GST, 1.5 nm for Sb2Te and AgIn-Sb2Te, and 1.3 nm for GeSb. The observed increase in the phase transition temperature with reduced film thickness and the fact that very thin films still show clear phase change properties are indications that Phase Change Random Access Memory technology can be scaled down to several future technology nodes.

Size Effects in Sputtered PZT Thin Films

1990 ◽  
Vol 200 ◽  
Author(s):  
Seshu B. Desu ◽  
Chien H. Peng ◽  
Lee Kammerdiner ◽  
Paul J. Schuele
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Size Effects ◽  
Ferroelectric Properties ◽  
Critical Discussion ◽  
Pzt Thin Films ◽  
Individual Contributions ◽  
Crystallite Dimension ◽  
Switching Characteristics ◽  
The Individual

ABSTRACTThe ferroelectric properties and switching characteristics of rf sputtered PZT thin films were investigated as a function of film thickness (30–300 nm) and grain size. Electron microscopy was used to characterize the film microstructure. The film thickness was measured by ellipsometer. The results were analyzed for the individual contributions of film thickness and crystallite dimension to the size effects on the properties of ferroelectric thin films. A critical discussion of several different models describing the size effects was also presented.

Short-wavelength optical storage properties of GeSb2Te4 phase-change thin films

1996 ◽  
Author(s):  
Liqiu Q. Men ◽  
Fusong S. Jiang ◽  
Chao Liu ◽  
Huiyong Liu ◽  
Fuxi Gan
Keyword(s):  
Thin Films ◽  
Phase Change ◽  
Short Wavelength ◽  
Optical Storage ◽  
Storage Properties

Effect of indium doping on Ge2Sb2Te5 thin films for phase-change optical storage

2005 ◽  
Vol 80 (8) ◽  
pp. 1611-1616 ◽  
Author(s):  
K. Wang ◽  
C. Steimer ◽  
D. Wamwangi ◽  
S. Ziegler ◽  
M. Wuttig
Keyword(s):  
Thin Films ◽  
Phase Change ◽  
Optical Storage ◽  
Indium Doping

Crystallization and Melting of Oriented Parent - Daughter Lamellae in Sheared Isotactic Poly(propylene)

2010 ◽  
Vol 63 (8) ◽  
pp. 1179 ◽  
Author(s):  
Andrew Phillips ◽  
Peng-wei Zhu ◽  
Chitiur Hadinata ◽  
Graham Edward
Keyword(s):  
Flow Direction ◽  
Growth Direction ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
Individual Contributions ◽  
Multiple Melting ◽  
The Individual ◽  
Poly Propylene ◽  
Induced Crystallization

Alpha isotactic poly(propylene) (α-iPP) exhibits a form of lamellar branching that is unique among semicrystalline polymers, where the branches have a distinct orientation relationship with the original crystalline lamellae. This is termed a parent–daughter relationship (PD). By allowing the structure to crystallize in an oriented form, a bimodal orientation of lamellae is developed and the individual contributions of PD lamellae can be observed using wide-angle X-ray scattering (WAXS). The present study investigated oriented PD lamellae during flow-induced crystallization and subsequent melting using time resolved rheo-WAXS. During crystallization the planes of the daughter lamellae were observed to curve towards the flow direction as they grew from their parent lamellae. This was explained by the influence of neighbouring daughter lamellae confining their growth direction. Oriented daughter lamellae were found to melt ~5°C lower than oriented parent lamellae, which provides a new explanation for the multiple melting behaviour observed in the melting thermograms of sheared α-iPP.

A Handbook to Eddic Poetry: Myths and Legends of Early Scandinavia, ed. Carolyne Larrington, Judy Quinn, and Brittany Schorn. Cambridge: Cambridge University Press, 2016, xii, 413 pp., 12 b/w ill.

Mediaevistik ◽  
2018 ◽  
Vol 31 (1) ◽  
pp. 366-366
Author(s):  
Albrecht Classen
Keyword(s):  
Old Norse ◽  
Entire Volume ◽  
Cambridge University ◽  
Critical Studies ◽  
Individual Contributions ◽  
The Many ◽  
The Individual ◽  
Made In ◽  
Scandinavian Literature

Eddic poetry constitutes one of the most important genres in Old Norse or Scandinavian literature and has been studied since the earliest time of modern-day philology. The progress we have made in that field is impressive, considering the many excellent editions and translations, not to mention the countless critical studies in monographs and articles. Nevertheless, there is always a great need to revisit, to summarize, to review, and to digest the knowledge gained so far. The present handbook intends to address all those goals and does so, to spell it out right away, exceedingly well. But in contrast to traditional concepts, the individual contributions constitute fully developed critical article, each with a specialized topic elucidating it as comprehensively as possible, and concluding with a section of notes. Those are kept very brief, but the volume rounds it all off with an inclusive, comprehensive bibliography. And there is also a very useful index at the end. At the beginning, we find, following the table of contents, a list of the contributors, unfortunately without emails, a list of translations and abbreviations of the titles of Eddic poems in the Codex Regius and then elsewhere, and a very insightful and pleasant introduction by Carolyne Larrington. She briefly introduces the genre and then summarizes the essential points made by the individual authors. The entire volume is based on the Eddic Network established by the three editors in 2012, and on two workshops held at St. John’s College, Oxford in 2013 and 2014.

Employee Surveys and Sensing

2020 ◽  
Keyword(s):  
Organizational Performance ◽  
Employee Engagement ◽  
Computational Linguistics ◽  
Full Range ◽  
Organization Culture ◽  
Employee Survey ◽  
Passive Data ◽  
Individual Contributions ◽  
Action Taking ◽  
The Individual

This volume comprises 27 chapters focused on the design and execution of employee survey programs. These chapters reflect the latest advances in technology and analytics and a pervasive emphasis on driving organizational performance and effectiveness. The individual chapters represent the full range of survey-related topics, including design, administration, analysis, feedback, and action-taking. The latest methodological trends and capabilities are discussed including computational linguistics, applications of artificial intelligence, and the use of qualitative methods such as focus groups. Extending beyond traditional employee surveys, contributions include the role of passive data collection as an alternative or supplement in a comprehensive employee listening system. Unique contextual factors are discussed including the use of surveys in a unionized environment. Individual contributions also reflect increasing stakeholder concerns for the protection of privacy among other ethical considerations. Finally, significant clarifications to the literature are provided on the use of surveys for measuring organization culture, strategic climate, and employee engagement.

Knowledge First

2017 ◽  
Author(s):  
J. Adam Carter ◽  
Emma C. Gordon ◽  
Benjamin W. Jarvis
Keyword(s):  
Philosophy Of Mind ◽  
Theoretical Background ◽  
Contemporary Research ◽  
Timothy Williamson ◽  
Research Themes ◽  
New Directions ◽  
Individual Contributions ◽  
The Individual

In this introductory chapter, the volume’s editors provide a theoretical background to the volume’s topic and a brief overview of the papers included. The chapter is divided into five parts: Section 1 explains the main contours of the knowledge-first approach, as it was initially advanced by Timothy Williamson in Knowledge and its Limits. In Sections 2–3, some of the key philosophical motivations for the knowledge-first approach are reviewed, and several key contemporary research themes associated with this approach in epistemology, the philosophy of mind and elsewhere are outlined and briefly discussed. The volume’s papers are divided into two broad categories: foundational issues and applications and new directions. Section 4 discusses briefly the scope and aim of the volume as the editors have conceived it, and Section 5 offers an overview of each of the individual contributions in the volume.

Sign in / Sign up

Export Citation Format

Share Document