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Study of the Mo/Si bilayer and CuSi system recording thin films for write-once optical disc
No full text近年來，提高光碟片容量的方法包含：藍光儲存技術、超解析近場光學光碟、多記錄層技術、多階技術及全像資料儲存……等等，其中以藍光儲存技術發展最快速。
本論文以金屬誘發結晶理論，鍍製半導體-金屬二元合金以及半導體/(金屬元素、半導體-金屬二元合金) bilayer做為無機可寫一次光碟片之記錄層材料。我們使用濺鍍製備Mo(7 nm)/Si(7 nm) bilayer、CuSi(16 nm)、Si(1.5~8 nm)/CuSi(16 nm) bilayer及Ge(1.5~8 nm)/CuSi(16 nm) bilayer記錄薄膜。由熱分析實驗結果得知，Mo(7 nm)/Si(7 nm) bilayer記錄薄膜在250℃~450℃之間會有一階段的反射率變化。CuSi(16 nm) 記錄薄膜在180℃~310℃之間會有一階段的反射率變化。Si(1.5~8 nm)/CuSi(16 nm) bilayer反射率的變化溫度有兩個階段，第一個階段約為150℃到250℃，第二階段約為300℃到350℃。Ge(1.5~8 nm)/CuSi(16 nm) bilayer反射率的變化溫度有兩個階段，第一個階段約為150℃到280℃，第二階段約為300℃到440℃。Mo(7 nm)/Si(7 nm) bilayer初鍍薄膜之TEM 電子繞射分析顯示具有Mo的結晶相，經過300℃、20 分鐘熱處理後會形成hexagonal MoSi2相，，經過500℃、20 分鐘熱處理後會形成hexagonal MoSi2和cubic Mo3Si相二相共存。CuSi(16 nm)初鍍薄膜具有Cu3Si的結晶相，經過300℃、20 分鐘熱處理後會形成Cu3Si和cubic Si二相共存。Si(1.5~8 nm)/CuSi(16 nm) bilayer初鍍薄膜具有Cu3Si的結晶相，經過300℃、20 分鐘熱處理後會形成Cu3Si和cubic Si二相共存，經過500℃、20 分鐘熱處理後，會有cubic Si成長的現象，且會有hexagonal Si相形成。Ge(1.5~8 nm)/CuSi(16 nm) bilayer初鍍薄膜具有Cu3Si的結晶相，經過300℃、20 分鐘熱處理後會形成Cu3Si、Cu3Ge和cubic Si三相共存，經過500℃、20 分鐘熱處理後會形成Cu3Si、Cu3Ge 、cubic Si和cubic Ge四相共存，且cubic Si隨著Ge厚度的增加而減少。BD碟片動態測試結果顯示：Mo(7 nm)/Si(7 nm) 以1X速度寫入時，最佳的jitter值為6.5%，以4X速度寫入時最佳的jitter值為6.8%。CuSi(16 nm) 以1X寫入速度寫入時，最佳的jitter值為8.9%。Si/CuSi在1X的寫入速度下，當Si層的厚度為1.5 nm、3 nm及6 nm時，相對應的最佳jitter值分別為7.5%、5.2%及7.9%。Ge/CuSi在1X的寫入速度下，Ge層的厚度為1.5 nm、3 nm及6 nm時，相對應的最佳jitter值分別為7.5%、7.6%及11.4%。Recently, the methods to increase data storage of optical disc inclouding of blue laser optical recording, super resolution near field structure, multilayer, multi-level, holographic data storage, etc, and the blue laser optical recording was developed more rapidily than the others.
In this study, metal induced crystallization (MIC) mechanism for alloy and bilayer structure of inorganic recording thin films was investigated. The Mo(7 nm)/Si(7 nm) bilayer, CuSi(16 nm), Si(1.5~8 nm)/CuSi(16 nm) bilayer and Ge(1.5~8 nm)/CuSi(16 nm) bilayer recording films were prepared by magnetron sputtering. Thermal analysis shows that the Mo(7 nm)/Si(7 nm) bilayer films have one phase transition step, which temperature is occurred at 250 oC ~450 oC. The CuSi(16 nm) film has one phase transition step, which temperature is occurred 180 oC ~310 oC. The Si(1.5~8 nm)/CuSi(16 nm) bilayer films have two phase transition steps, which temperatures are occurred at 170 oC ~250 oC and 300 oC ~350 oC. The Ge(1.5~8 nm)/CuSi(16 nm) bilayer films have two phase transition steps, which are occurred at 150 oC ~280 oC and 300 oC ~440 oC. The TEM analysis shows that the as-deposited Mo(7 nm)/Si(7 nm) bilayer film is amorphous, and it would transform to the hexagonal MoSi2 phase after annealing at 300 oC for 20 mins. After annealing at 500 oC for 20 mins, it would transform to the hexagonal MoSi2 and cubic Mo3Si coexisting phases. The as-deposited CuSi(16 nm) film has Cu3Si phase, and it would transform to the Cu3Si and cubic Si coexisting phases after annealing at 300 oC for 20 mins. The as-deposited Si(1.5~8 nm)/CuSi(16 nm) bilayer films have Cu3Si phase, and it would transform to the Cu3Si and cubic Si coexisting phases after annealing at 300 oC for 20 mins. The grain size of cubic Si phase increases after annealing at 500 oC for 20 mins, and the hexagonal Si phase would be formed. The as-deposited Ge(1.5~8 nm)/CuSi(16 nm) bilayer films have Cu3Si phase, and it would transform to the Cu3Si, Cu3Ge and cubic Si coexisting phases after annealing at 300 oC for 20 mins. After annealing at 500 oC for 20 mins, it would transform to the Cu3Si, Cu3Ge, cubic Si and cubic Ge coexisting phases, and the amount of cubic Si phase decreases with the increasing of the Ge layer thickness. The dynamic tests show that the jitter value of Mo(7 nm)/Si(7 nm) bilayer film is 6.5% under 1X BD recording situation and 6.8% under 4X BD recording situation. The jitter value of CuSi(16 nm) film is 8.9% under 1X BD recording situation. On the other hand, the jitter values of Si/CuSi bilayer films are 7.5%, 5.2%, and 7.9% under 1X BD recording situation as the Si layer thickness are 1.5 nm, 3 nm, and 6nm, respectively. The jitter values of Ge/CuSi bilayer films are 7.5%, 7.6%, and 11.4% under 1X BD recording situation as the Ge layer thickness are 1.5 nm, 3 nm, and 6nm, respectively
Crystallization mechanisms and recording characteristics of Si/CuSi bilayer for write-once blu-ray disc
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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