8,862 research outputs found
Fabrication of Nanoslits with <111> Etching TSWE Method
No full textIn this paper, we report a modified three step anisotropic wet etching (TSWE) method to fabricate solid-state silicon nanoslits. The slit-opening process is performed by <111> crystal plane etching. The etching rate of the <111> crystal plane is reasonably slow as it is only 1/45 of the <100> etching rate, thus allowing and therefore good slits-opening controllability. By slowly etching the <111> crystal plane, the over-etching was effectively reduced. Perfectly rectangular nanoslits with different dimensions were successfully obtained. The smallest achieved feature size of the nanoslit is 8.3 nm.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic Components, Technology and Material
The construction of Karen Karnak: The multi-author-function
No full textThis thesis is situated within the comparatively recent developments of Web 2.0 and the emergence of interactive WikiMedia, and explores the mode of authorship within a Read/Write culture compared to that of a Read/Only tradition. The hypothesis of this study is that the role of the audience has become merged with the author, and as such, represents new functions and attributes, distinct from a more conventional concept of authorship, in which the roles of audience and author are more separate. Read/Write and participatory culture, as defined by this study, is focused on collaboration, and includes the influences of D.I.Y. culture, Open-Source practices and the production of text by multiple authors. Multi-authorship presents a re-thinking of several concepts which support the notion of the individual author, since the focus of multi-authorship is not on attribution and ownership of a finished text, but on the continued malleability of a text. Modes of multi-authorship, demonstrated in the use of the pseudonyms Alan Smithee and Karen Eliot, represent declarative authors whose names signify multiple origins, whilst concurrently indicating a distinct body of work. The function of these names form an important context to this study, since primary research involves the construction of an experimental mode of multi-authorship utilising WikiMedia technology and the interaction of thirty nine participants, who are invited to create a body of work under the collective pseudonym Karen Karnak. The data generated by this experiment is analysed using aspects of Michel Foucault's author-function to identify and determine power structures inherent in the WikiMedia context. The interplay of power structures, including concepts such as identity, ownership and the body of work, affect the resulting mode of authorship and contribute to the construction of Karen Karnak, suggesting further areas of research into the emerging multi-author
Ag/Ni/Pt(111)與Ni/Ag/Pt(111)之結構比較研究
No full text[[abstract]]本實驗室中我們將以歐傑電子能譜（AES, Auger Electron Spectroscopy）、低能電子繞射（LEED, Low Energy Electron Diffraction）、紫外光電子能譜術（UPS, Ultraviolet Photoelectron Spectroscopy）與離子濺射來了解Ag / Ni / Pt (111)與Ni/ Ag /Pt (111)兩種對稱系統結構合金形成的過程。
0.5 ML Ag / x ML Ni / Pt (111)的樣品（x = 1，2，3）在溫度的影響下，銀原子隨著整個升溫過程一直維持在最表面的狀態，而鎳原子隨著鎳的厚度增加，開始往鉑擴散所需的溫度也增加。當鎳的層數為1ML，2ML，3ML時，開始擴散溫度分別為500 K、600 K、700 K。同樣地，1 ML Ag / x ML Ni / Pt (111)的樣品（x = 1，2，3），銀原子在整個升溫過程仍然維持在最表面的狀態，而鎳原子隨著鎳的厚度增加，開始往鉑擴散所需的溫度也增加。當鎳的層數為1ML，2ML，3ML時，開始擴散溫度分別為520 K、620 K、710 K。
x ML Ni / 1 ML Ag / Pt (111)的樣品（x = 1，2，3，4）在升溫過程中，我們發現鎳原子與銀原子也有交換的現象，銀原子大約在400 K左右開始與鎳交換擴散至表面，直到完全擴散至表面後，鎳才開始擴散至鉑形成合金。隨著鎳的厚度增加，銀完全擴散至表面及鎳開始擴散至鉑的溫度也一同隨之增加。當鎳的層數為1ML，2ML，3ML，4ML時，開始擴散溫度分別為534 K、620 K、700 K、750 K。
從離子濺射作結構的深度分析中，可以發現1ML Ag / 1 ML Ni / Pt (111)與1ML Ni / 1 ML Ag / Pt (111)在合金後，結構組成皆成為銀原子覆蓋在表面的鎳鉑合金結構。不論是Ag / Ni / Pt (111)或是Ni / Ag / Pt (111)系統中在相同鎳的層數之下，鎳鉑開始合金溫度是近乎相同的。也就是Ni / Ag / Pt (111)系統在銀完全擴散至表面後的結構組成與Ag / Ni / Pt (111)系統相似。
在Ag / Ni / Pt (111)或是Ni / Ag / Pt (111)系統中，樣品的升溫過程都是不可逆的反應，當我們將樣品升至830 K後，再降回室溫，整個降溫過程中發現結構組成並沒有隨溫度變化了。
Co/Ni/Pt(111)的磁性研究
No full text[[abstract]]Experiments were performed in situ in a stainless ultrahigh vacuum (UHV) chamber. In situ magneto-optical Kerr effect (MOKE) was used to study the magnetic properties of the
system.
I study the magnetic properties of ultrathin Co films on Pt(111) with Ni buffer layers. We prepare dCo Co/1 ML Ni/Pt(111), and the Kerr signals measured at room temperature. The polar and longitudinal Kerr signal was not exist for 0 ~ 3 ML Co/1 ML Ni/Pt(111). The easy axis of the magnetization for 4&5 ML Co/ Pt(111) is in-plane. We find the same result, when dCo Co/1 ML Ni/Pt(111) was prepare at 450K, and the Kerr signals measured at 450K or at room temperature. If we prepare dCo Co/1 ML Ni/Pt(111) at RT, and the Kerr signals measured at 450K. The easy axis of the magnetization for 1 ML Co/ Pt(111) is out-of-plane. The polar and longitudinal Kerr signal was not exist for 2&3 ML Co/1 ML Ni/Pt(111). The easy axis of the magnetization for 4&5 ML Co/ Pt(111) is in-plane. The variation of AES of 1 ML Co/1 ML Ni/Pt(111) as a function of sample temperature. We find the mixing of Ni and Co layers occurs at 420K. The formation of Co-Pt alloy causes the perpendicular magnetic anisotropy.
I also study the magnetic properties of ultrathin Ni films on Pt(111) with Co buffer layers. The easy axis of the magnetization for 1 ML Co/ Pt(111) is out of plane. We were surprised that only the polar Kerr signals were observed when dNi 24 ML. Studies of the magnetic properties showed that the easy axis of the magnetization changed from the cant to the out-of-plane direction when the Co buffer layer was inserted on Ni/Pt(111).
After different temperature annealing, cause the different competition alloy. The competition in the alloy formations between Co-Pt and Ni-Pt in the Co/Ni/Pt(111) and Ni/Co/ Pt(111) system is also interesting, cause the different magnetic properties. I also try to understand that.
A comparative study in CCl4 reaction on Ag/Si(111) surfaces: PEEM and PES investigations
No full textA comparative study in CCl4 reaction on Ag/Si(111) surfaces: PEEM and PES investigations
Yunxi Yao, Qiang Fu, Xinhe Bao
State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P.R. China
We report a comparative study in the reactivity of bulk Ag(111), monolayer Ag film on Si(111), and Si(111)-77 surfaces via X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), photoemission electron microscopy (PEEM), and scanning tunneling microscopy (STM). The monolayer Ag film grown on Si(111), which is known as √3×√3-Ag-Si surface structure, was obtained by depositing one monolayer Ag on the Si(111)-77 surface at 550 K. The most simple halogen methane, CCl4, was chosen as the probe molecule to study the surface reactivity of the bulk Ag(111) surface, the monolayer Ag film, and the Si(111) surface. XPS and UPS data indicate that the monolayer Ag film presents unique reactivity to CCl4 in comparison to the other two surfaces. For the PEEM study, a dedicated sample consisting of bulk Ag particles supported on the monolayer Ag film was prepared as shown in the schematics in Fig. 1. In situ PEEM imaging of the surface reaction in presence of CCl4 shows a gradual change in the grey intensity from bright to totally dark on the Ag particles but little change on the √3×√3-Ag-Si surface. The grey intensity decrease is due to local work function increase from the dissociated Cl atoms. The experiments suggest that monolayer Ag is inert toward dissociation of CCl4 compared to the Ag(111) and Si(111) surface. It has proposed that the confinement of 5sp electron of Ag atoms in the √3×√3-Ag-Si surface, which is delocalized in the bulk Ag(111) surface, is decisive to the different reactivity.
Figure 1: (a) Schematic representation of the √3×√3-Ag-Si surface supported Ag islands; (b) PEEM image of the Ag islands/√3×√3-Ag-Si sample before CCl4 exposure. Field of view (FoV) is 27 μm; (c) PEEM image shows the same area in (b) but after 24 L (5.2×10-9 mbar × 6000 s) CCl4 exposure; (d) the work function change (ΔΦ) of the Ag(111) and √3×√3-Ag-Si surfaces when exposed to different amount of CCl4 at RT, measured from PES results.
References:
[1] Y.X. Yao, X. Liu, Q. Fu, W.X. Li, D.L. Tan, X.H. Bao, ChemPhysChem 2008, 9: 975-979.
*Corresponding author: Fax: +86-411-84694447, E-mail: [email protected], [email protected]
Arendt, Hannah–Ephemera 111
No full text111 Found in Peace in the Middle East: Contained ephemera : a publisher\u27s order form for this title found between pp. 48-49; a printed card with a statement by the author found between pp. 94-95; a printed card indicating that the book was sent with the compliments of the publisher, also found between pp. 94-95.https://digitalcommons.bard.edu/hapl_ephemera/1094/thumbnail.jp
El Tlacuache Núm. 111 (2003). 111 Año 3 (2003) diciembre. El Tlacuache
No full text- Fiestas decembrinas por Maria Cristina Saldaña Fernández. - El Yauhtli por Margarita Avilés y Macrina Fuentes
Surface characterization of AlGaN grown on Si (111) substrates
No full textUp to 500 nm thick crack-free Al(0.25)Ga(0.75)N and Al(0.32)Ga(0.68)N epilayers have been grown on Si (111) substrates. The surface morphology of samples was investigated by an optical microscope and a scanning electron microscope (SEM). Pits and shale-like surface structure have been observed. XRD rocking curve measurements indicate the crystal quality of samples. The analyses show that the Al source flux is an important factor in growing AlGaN on Si (111). The information from the Micro-Raman spectra supported that Al atoms are gathered at nearby areas of the pits originated from the AlN/Si (111) interface in the initial stage of AlGaN growth. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved
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