نتایج جستجو برای: stoichiometry defect

تعداد نتایج: 104337  

پایان نامه :دانشگاه تربیت معلم - تهران - دانشکده علوم 1390

به منظور مطالعه آستانه تخریب لیزری، لایه های نازک tio2وzro2 به روش تبخیر بیم الکترونی روی زیرلایه bk7 لایه نشانی شدند سپس به مدت 3 ساعت با گرادیانهای مختلف دمایی تحت عملیات حرارتی قرار گرفتند؛ با استفاده از پراش پرتوی ایکس(xrd)، میکروسکوپ نیروی اتمی(afm)، طیف سنجuv-vis و طیف سنجی فوتوالکترون با پرتوی ایکس(xps)، مشخصات اپتیکی، ساختاری، ریخت شناسی و ترکیب شیمایی بدست آمد. آستانه تخریب لیزری با اس...

Journal: :Nanoscale 2015
Felix Gunkel Sebastian Wicklein Susanne Hoffmann-Eifert Paul Meuffels Peter Brinks Mark Huijben Guus Rijnders Rainer Waser Regina Dittmann

The electrical properties of the metallic interface in LaAlO3/SrTiO3 (LAO/STO) bilayers are investigated with focus on the role of cationic defects in thin film STO. Systematic growth-control of the STO thin film cation stoichiometry (defect-engineering) yields a relation between cationic defects in the STO layer and electronic properties of the bilayer-interface. Hall measurements reveal a sto...

Journal: :Journal of the Japan Institute of Metals and Materials 1993

پایان نامه :وزارت علوم، تحقیقات و فناوری - پژوهشگاه دانشهای بنیادی (مرکز تحقیقات فیزیک نظری و - پژوهشکده علوم نانو 1392

among the low–dimensional allotropes of carbon, nanotubes and graphene have attracted very much attention from nano–science and nanotechnology specialists. they have been proposed as building blocks in nanometer device engineering. however, these structures are not defect–free. in this thesis, we focused on defective carbon nanotubes and graphene, and studied the effect of couple of very common...

1997
Alex Zunger Su-Huai Wei

Using rst-principles self-consistent electronic structure theory, we have calculated defect formation energies and defect energy levels in CuInSe2. Contrary to previously accepted assumptions in the analysis of defects in CuInSe2 we nd that (i) it is much easier to form Cu vacancy in CuInSe2 than to form cation vacancies in II-VI's. (ii) Defect formation energies vary considerably both with the...

Journal: :Physical review letters 2013
Donghun Kim Dong-Ho Kim Joo-Hyoung Lee Jeffrey C Grossman

Although the stoichiometry of bulk lead sulfide (PbS) is exactly 1:1, that of quantum dots (QDs) can be considerably different from this crystalline limit. Employing first-principles calculations, we show that the impact of PbS QD stoichiometry on the electronic structure can be enormous, suggesting that control over the overall stoichiometry in the QD will play a critical role for improving th...

2004
J. Zhang Y. Zhao Y. Wang T. Uchida

Introduction Transition-metal monoxides, such as NiO, CoO, FeO, and MnO, have been receiving considerable attention as model materials for elucidating defect structures, the nature of interaction between defects, and effect of nonstoichiometry on physical properties. Wüstite is an iron oxide that possesses rock-salt structure and exhibits a wide range of nonstoichiometry (0.88 < x < 1 in FexO)....

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