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Nanoscale Material Characterization of Silicon Nanowires for Application in Reconfigurable Nanowire TransistorsBukovsky, Sayanti 26 July 2021 (has links)
Silicon Nanowire based Reconfigurable Field Effect Transistor (SiNW RFET) presents a solution to increase the system functionality beyond the limits of classical CMOS scaling in More-than-Moore era of semiconductor technology. They are not only spatially reconfigurable, i.e., the source and the drain can be interchangeable in design, but in such devices one can also control the primary charge carrier by controlling the voltage in the control gate. The two key morphological factors controlling reconfigurability are the structure and composition of the Schottky junctions, which serve as the location for Program and Control gates and radial strain induced by the self-limiting oxidation, which influences the carrier mobility resulting in symmetric p and n characteristic curves of an RFET. Despite its potential, in-depth nanoscale studies on the structural and compositional characterization of the key features controlling the reconfigurability are limited and thereby presents as a novel area of research.
In this study, the composition and morphology of the Schottky junction and the radial strain profile due to self-limiting oxidation were studied using advanced imaging and sample preparation techniques like Transmission Electron Microscope (TEM) and Scanning Electron Microscope (SEM) imaging alongside with precise sample preparation methods like Focused Ion Beam (FIB) liftout techniques.
For analysis of radial strain in nanowires that underwent self-limiting oxidation, a TEM lamella was taken of a cross-section of the NW. The lamella was kept at 200 nm thickness to preserve the strain state of the nanowire cross-section.
It was observed that nanowires undergoing such oxidation have an omega (Ω) shaped oxide shell where the shell was discontinued at the spot where the nanowire was touching the substrate. Fast Fourier transform of the high-resolution image of such a NW crossection was used to calculate the strain profile.
The strain is also found to be not radially uniform for such Ω shaped oxide shells. The strain profile shows a local maxima near the nanowire base where it touches the substrate then a minima approximately at the geometric center followed by the maximum strain at the area adjacent to the oxide shell thereby showing a sinusoidal profile. Theoretical simulations performed by Dr. Tim Baldauf further verified the nature of the sinusoidal strain that was observed experimentally. Similar simulations were done for different omega shell shapes, which yielded strain plots of similar sinusoidal strain plots, with the local maxima depending on the level of encapsulation of the NW by the shell.
In the characterization of the Schottky junction, a TEM lamella was taken along the longitudinal direction of a nanowire, which was silicidized from both ends, similar to ones used in SiNW RFET devices. High resolution TEM micrographs and EDX (Energy dispersive X-Ray Spectroscopy) in the TEM along the Schottky junction showed a Ni rich phase and pure Si on either side of the junction. This participating phase was identified as NiSi2. However, the transition between the phases shows a gradient and in-situ experiments were designed to verify the sharpness of the junction.
In in-situ silicidation experiments, Si nanowires with a thin native oxide shell were distributed on an electron transparent surface and were partially covered with Ni islands by shadow sputtering. The whole setup was then heated in a heating stage of a TEM and the Ni was allowed to disperse within the Si nanowires forming NiSi2. HRTEM (High Resolution TEM), EDX and EELS (Electron Energy Loss Spectroscopy) studies were performed on the silicidized samples for further ex-situ analysis.
During the in-situ experiment, it was observed that Ni-phase interface is atomistically sharp and seldom progresses perpendicularly to the nanowire’s direction but through the closed packed planes of the NW. The interface velocity at different temperatures was used to calculate the activation energy of the silicidation process. The value of the activation energy indicates the Ni undergoing volume diffusion through the Ni-rich phase. The velocity of the interface was observed to be much higher in nanowires with smaller diameters than those with higher diameters, further proving the hypothesis.
During the in-situ experiments, in around 10% of nanowires that underwent complete silicidation and held isothermally, the crystalline silicide phase was observed to partially or fully diffuse out of the nanowire core, leaving only a thin shell of Silicon oxide forming ultra-thin walled SiO2 nanotubes (NT).
The onset and the time required for completion of the process varies in the nanowires depending on size of the nanowire, the distance and contact to the nearest Ni islands and presence of defects such as kinks and twists within the nanowire.
In order to study the dynamics of the process, the velocity of the receding front was calculated for nanowires of two different diameters. They are found to be identical, indicating the volume flow rate of the process is directly proportional to the cross-sectional area. The voids were formed by the reduced diffusivity of Ni in Ni2Si phase in comparison to phases with lower percent of Ni. This indicates that the reason behind the phenomenon is coalition of Kirkendall voids and thus dependent on volume diffusion.
From this study, it can be concluded that the extent of self-limiting oxidation and shape of the shell can influence the radial strain state. This can be used to manipulate the strain to tailor the electron and hole transfer characteristics within the RFET. A variety of factors including temperature, time, orientation and radius of the nanowires has been studied with respect to silicidation of a SiNW. The calculated activation energy can be used for precise process control over the location and morphology of Schottky junction. Although not directly related to SiNW RFET devices, the self-assembly of ultra-thin-walled SiO2 NT is a novel research area in itself, the findings of which can be applied in to design novel electronics and sensors.:TABLE OF CONTENTS
Preface
List of Abbreviations
CHAPTER 1: Introduction and Motivation
1.1 Definition and History
1.2 Synthesis Routes
1.3 Properties and Applications
1.4 Nanoscale Electronics and Role of Si Nws
1.4.1
1.4.2 SiNW Reconfigurable Field Effect Transistor
1.5 Introduction to The Topic of The Thesis
1.6 Outline of The Thesis
CHAPTER 2: Physical Basics and Previous Research: A Short Summary
2.1 Strain Measurement and Effects of Strain on on Nanoelectronics
2.1.1 Strain Analysis in Planar CMOS Structures
2.2 Silicidation and Schottky Junction
2.2.1 In-situ Silicidation
2.2.2 Silicon oxide nanotubes
CHAPTER 3: Background of Instruments and Experimental Set-up
3.1 Scanning Electron Microscope
3.2 Transmission Electron Microscope
3.2.1 Imaging Techniques
3.2.2 TEM sample preparation
3.3 Focused Ion Beam
CHAPTER 4: Strain in Nanowire
4.1 Goal of This Study
4.2 Strain in SiNW RFET Devices
4.3 Strain Analysis in SiNW Cross-section
4.3.1 Sample Preparation
4.3.2 Experimental Process
4.3.3 Results and Discussion
4.4 Conclusions
CHAPTER 5: Schottky Junction
5.1 Crystallographic Data on Nickel Silicides
5.2 Formation of Silicides in 2-D Structures
5.2.1 Sample History
5.2.2 Sample Preparation
5.2.3 Results and Discussion
5.3 Formation of Silicides in 1-D Structures: Schottky Junction in NWs
5.3.1 Sample History
5.3.2 Sample Preparation
5.3.3 Results and Discussion
5.3.4 Shortcomings of The Lift-out Technique
5.4 In-situ Silicidation
5.4.1 Motivation
5.4.2 Sample Preparation
5.4.3 Experimental Procedure
5.4.4 Results and Discussions
5.4.5 Shortcoming of The Experiment
5.5 Self-assembling SiO2 Nanotubes
5.5.1 Sample Preparation
5.5.2 Experimental Process
5.5.3 Results and Discussion .
5.5.4 Post In-situ Experiment TEM Analysis
5.5.5 Conclusions
CHAPTER 6: Conclusions and Outlook
6.1 Strain Analysis
6.2 Schottky Junction Studies
Bibliography
Acknowledgements
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Intenzivní dům v Brně / Intenzive Urban Housing BrnoJabůrková, Dominika January 2016 (has links)
The aim of this Master thesis was to create urban structure situated in the particular resident area of Brno city centre. The solution offers mixing of different functions (living, shopping, workshops, offices, restaurant, other services and working possibilites) on a relative small built up area.This is realized with a help of two main principes/multiplicity and verticality. The efective use of the area was achieved with dividing the space to the „calm“areas and „busy“ areas. Calm areas are a park in courtyard and the roof gardens, busy area is a new diagonál street with shops, restaurant, fastfood and galery. The objects have different height, the highest one is 12 floors tall. In the first one are different functions as kindergarten, shops, administrative, gallery, insurance, coffee, in the second one there is partly administrative and infant school. Flats and studios are designed from the second floor to the 11 floor. The 12th floor offers a coffeebar with a view of Brno dominants. There is parking and technical device space in the two underground floors. The construction system is reinforced concrete monolitic skelet with girders, the horizontal constructions are reinforced monolitic plates. The buildings are founded on reinforced concrete flaps.
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Vývoj pojetí světové duše u Henryho Mora / The Evolution of the notion of a World Soul in Henry MoreJoseph, Jacques January 2018 (has links)
The main goal of this thesis is to describe the evolution of the concept of a world soul in the thought of Cambridge Platonist Henry More (1614-1687). However, this topic is discussed within the broader context of early modern philosophy and the birth of modern science. The philosophy of Henry More presents a very interesting confrontation between Renaissance Neo-Platonism and Cartesianism, early modern mechanicism and the newest scientific discoveries of his age, the notion of a world soul being exactly the point where all these thought currents meet. The classical conception of a platonic world soul in More's early thought later becomes the Spirit of Nature, a principle complimentary to mechanicism (and at the same time acting as its metaphysical foundation). Yet in order for the regularity of such phenomena as gravitation to be guaranteed, the Spirit of Nature has to be rid of any conscience and will of its own. However, besides this tendency to "strip" the world soul of its personal aspects, leading ultimately to the notion of a completely impersonal natural law, a deeper analysis of certain aspects of More's philosophical system shows also a determination to preserve the broader connections that tie the classical notion of a world soul to a specific world picture that does not necessarily fit...
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”Det är öppet mer, helt enkelt.” : Meröppen biblioteksverksamhet i Göteborgs Stad. / “It’s simply open more.” : More-open library services in the City of Gothenburg.Kaan, Cecilia January 2021 (has links)
In 2017, the City of Gothenburg implemented its first more-open unstaffed self-service library station. The following year, the first more-open library was implemented. The purpose of this thesis has been to increase the understanding of more-open library services and to investigate how they are presented in public documents and by representatives of the City of Gothenburg's cultural administration and culture committee. The theoretical framework consists of elements from neo-institutional organisational theory. The starting point is the view of organisations as part of an institutional context where the understanding of organisational development and change is analysed by looking at factors surrounding the organisation. Concepts such as legitimacy, organisational isomorphism and organisational fields are central to the work. The study has been conducted through a mixed-method approach and consists of a document study of public documents and a semi-structured interview study with three library managers, the chairperson for the culture committee and an official from the culture administration. The material has then been analysed through a qualitative content analysis where themes have been identified in the data collection. The study concludes that more-open library services are considered a complement to regular library activities. Above all, more-open library services are justified by increased accessibility to libraries and culture for members of the public. Even though not everyone can use more-open libraries, the more-open services are considered to increase the total accessibility in the city. The study has found some perceived prerequisites for more-open libraries, which can be summarized as follows: a suitable library facility, a quiet local environment with the library placed within a certain context, time for planning activities, technical resources, a pedagogical approach, and independent users who can handle self-service technique. More-open library services can both gain legitimacy and be legitimized with reference to increased availability and efficient use of tax funds. This is a two-year master’s thesis in Library and Information Science.
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Vliv politiky zaměstnanosti na postavení osob 50+ na trhu práce: případová studie okresu Vsetín / Influence of employment politics on situation of people at the age of 50+ on the labour market: case of the Vsetín districtZemanová, Iva January 2011 (has links)
The thesis: "Influence of employment politics on situation of people at the age of 50 + on the labour market: Case study of the Vsetín district" deals with problems of older people's position on the labour market in the Czech Republic focusing on the Vsetín district and influence of employment policy on this position. This thesis characterizes the group of people at the age of 50 and more as labour power and deals with their strategies on the labour market. It also deals with employment policy of the European Union related to the group of people at the age of 50 and more on the labour market and analyses strategic documents of the Czech Republic solving these problems in detail. Furthermore this thesis focuses on the employment policy of the Czech Republic, mainly on analysis of functions, possibilities, limits and influence of chosen tools of the active employment policy on the lowering of the number of the unemployed people who belong to the above mentioned age-group on the labour market. It evaluates these tools in detail and shows which of these examined tools have the biggest influence on the lowering of the number of the unemployed older people. In the practical part it deals with case study of a practical example of a possible solution of the problem of unemployment of people at the age of...
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Evropská kulturní lobby. Případ kampaně We are more / European Cultural Lobby. The Case of We Are More CampaignFrajtová, Věra January 2013 (has links)
Master thesis "European cultural lobby. Case of We Are More campaign" is analyzing the European lobbying in the cultural domain. As an area of European policies, culture has been established continuously since the 80's of the 20th century. The role that culture gained at the European Union (EU) level is specific by its double dimension. At the same time, culture is perceived as a source of common values and an area with high economic potential. This thesis examines whether the exclusive role of culture within the EU signifies specific features of lobbying in the cultural domain. Theoretical part of this work is using the concept of europeanization in order to explain how culture became an area of European public policy. The same part develops the theory of European lobbying to demonstrate division of the EU interest groups into public and private. Second part of this thesis presents the case study of the nowadays biggest European cultural lobby, Culture Action Europe, and We Are More campaign organized by this lobby in order to influence future European framework programmes for culture and audiovisual in 2014-2020 period. Features that decide whether an interest group is public or private, as defined by the theoretical part of this thesis, are studied on the case of Culture Action Europe. In order to...
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The rhetoric of Sir Thomas More and Dietrich Bonhoeffer in original work and dramatic portrayalHarvey, Robert C. 01 January 1971 (has links)
Chapter I. This is a critical study of the rhetoric of Sir Thomas More and Dietrich Bonhoeffer and of plays in which they are portrayed. The purpose is to discover whether or not the rhetoric of the playwrights preserves the integrity of the ideas of the central characters as evidenced by the rhetoric found in their original works .
Chapter II. Rhetorical criticism is rendering a judgment on the fitness, correctness or appropriateness of those discourses, spoken or written the aim of which is to influence the readers or hearers. There is much variety in methods of rhetorical criticism. This study will use the dramatistic pentad proposed by Kenneth Burke. Its elements are act, agent, agency, scene and purpose. It will also employ the naming of strategies, another term from Burke meaning methods or attitudes. In addition judgments will be made on the basis of significant ideas, creative choice of language, integrity and credibility.
Chapter III. Sir Thomas More was a lawyer, scholar and public official in England at the time of King Henry VIII. He incurred the King’s displeasure by his refusal to support him in his efforts for a divorce. He believed strongly in the need to preserve one’s integrity by obeying his conscience. In his trial speech, his main strategies were related to the importance of conscience and his knowledge of the law. He was pronounced guilty of treason and executed.
Chapter IV. In a Man for All Seasons, the playwright has used several theatrical strategies that help to focus attention on More, the central character. He is presented as a genial man of firm reliance on the law and obedience to his conscience. On the basis of a comparison of the rhetoric in the play with that of More, it is concluded that the playwright faithfully preserved the integrity of More’s ideas.
Chapter V. Dietrich Bonhoeffer was a theologian, pastor and teacher of Germany during the Nazi regime. He opposed the Nazis on theological grounds, and gradually came to believe that he must become active personally and politically. He joined the resistance movement in a plot to assassinate Hitler. He was imprisoned and executed. His chief motive for action was obedience to God. In selected writings, he is seen to have a strong faith in God, and great hope for the future.
Chapter VI. The Cup of Trembling is a play based on the life of Dietrich Bonhoeffer, though using mostly fictional names. Again, the playwright uses devices that bring out the hero’s character. His struggle against the Nazis is seen to involve a corresponding struggle within himself as he makes decisions about his role in the situation. His faith in God and obedience to God are expressed, as well as his hope for the future. On the basis of similar ideas expressed in both media, it is concluded that the playwright succeeded in preserving the integrity of Bonhoeffer’s ideas.
Chapter VI I. The key idea of conscience is seen to have been preserved by both playwrights. A number of major ideas were traded from the original figure to the play, and their integrity was seen to be preserved. Therefore, it is concluded that the playwrights did preserve the integrity of the ideas of the two men in the rhetoric of their plays. The major implication of this conclusion is that drama is an effective means of expressing the rhetoric of important historical figures.
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Tvorba zpřesněného rastru sáhové katastrální mapy v katastrálním území Těchanov / Creation more accurate raster of the cadastral map in the cadastral district TěchanovVálková, Zuzana January 2012 (has links)
The thesis is dedicated to creation more accurated raster of the cadastral map in the cadastral district Těchanov. In the introductory part theoretical findings from the area of more accurate transformation are summarized and several terms related to raster problemacy are explained. The following chapter deals with the used software. Another part deals with description of the practical part, i.e. making out transformational key accurating transformation. The final chapters are dedicated to verifying the result of transformation by an independent control using the comparison of lenghts directly measured in terrain, measured on the original map of land cadastral or cadastral map and lenghts discovered from raster scan images before and after accurating transformation.
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Series Dc Arc Characterization, Prevention & Detection inAircraft SystemsBauer, Eric Charles 09 July 2019 (has links)
No description available.
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AI as a tool and its influence on the User Experience design process : A study on the usability of human-made vs more-than-human-made prototypesPop, Mira, Schricker, Max January 2023 (has links)
This research paper delves into the integration of artificial intelligence (AI) in the process of user experience (UX) design resulting in more-than-human-made designs. Specifically, the study focuses on the utilization of the text-to-image AI tool, Midjourney. The primary research questions addressed in this paper are twofold: 1) How do AI tools influence the current UX design process of a high-fidelity prototype? and 2) How do more-than-human-made high-fidelity prototypes compare with human-made high-fidelity prototypes in terms of UX? To answer these research questions, a two-method study design was employed. Firstly, two focus groups with in total of 8 designers as participants were formed, with one group utilizing Midjourney to investigate its influence on the design process and to compare the two groups regarding their workwise. The aim was to create two comparable prototypes within a specific e-commerce setting. Secondly, a between-subjects design user study with 32 participants was conducted to test the high-fidelity prototypes and to assess any potential disparities in UX quality between them. The findings regarding the first research question indicate that Midjourney primarily serves as an inspirational tool. Designers were able to harness the AI tool to generate dark mode images, with the final chosen dark mode exemplifying the impact of Midjourney. Additionally, designers attempted to utilize the tool for creating icons. Regarding the second research question, the user study revealed that, despite similar and comparable use cases, there were only minor significant differences in terms of UX quality. The overall scores in System Usability Scale (SUS) and User Experience Questionnaire Plus (UEQ+) did not exhibit any significant disparity. This study suggests that while Midjourney proves to be a useful tool within the design process, its current influence on designers' UX design process and the ultimate performance of the final prototype remains relatively modest. Further research and development may be required to enhance its impact in the field of UX design and the study design should be used to test other AI tools in comparable settings.
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