نتایج جستجو برای: band gap energy

تعداد نتایج: 899121  

Bigdeli, Tania, Motiee, Fereshteh,

Introduction: In this research, TiO2-Zr nano-photocatalyst was firstly developed with the aim of improving the photocatalytic activity of titanium dioxide via sol-gel method. The recovery of catalysts in acidic, alkaline and thermal conditions was also studied. Method: This research was done on a laboratory scale. The structures and properties were recognized with (BET), (FT-IR), (FE-SEM), and...

Journal: :Physical review. B, Condensed matter 1995
Picozzi Continenza Freeman

The structural and electronic properties in common-anion (GaSb) 1 /(InSb) 1 and common-cation (InAs) 1 /(InSb) 1 [111] ordered super-lattices have been determined using the local density total energy full potential linearized augmented plane wave method. The influence of the ordering direction, strain conditions and atomic substitution on the electronic properties of technological and experimen...

2008
Steven Jenks

Introducing intermediate band(s) within the energy gap of the semiconductor could possibly increase efficiencies of solar cells. Photons with energy less than the band gap can contribute to the device output by using the intermediate band(s) as a ‘ladder’ to the conduction band. The present analysis shows the maximum efficiency an ideal solar cell containing one and two intermediate bands can a...

2009
Michael Sentef Jan Kuneš Philipp Werner Arno P. Kampf

We study a model of a covalent band insulator with on-site Coulomb repulsion at half filling using dynamical mean-field theory. Upon increasing the interaction strength the system undergoes a discontinuous transition from a correlated band insulator to a Mott insulator with hysteretic behavior at low temperatures. Increasing the temperature in the band insulator close to the insulator-insulator...

پایان نامه :دانشگاه تربیت معلم - تبریز - دانشکده علوم 1389

فیلتری باساختارپریودیک سه گانه یک بعدی مطرح شده وروابط پراکندگی در ان بررسی میشود.با انالیز ریاضی می توان باندهای ممنوعه و مجاز طول موجها را با تغییرات زاویه فرودی پیش بینی کرد.با استفاده از روابط پراکندگی و با انتخاب مقادیر مناسب پارامترهای کنترلی میتوان طرح یک فیلتر اپتیکی را داد که می تواند در همه رنجهای طیف الکترومغناطیسی بکار گرفته شود.این مطالعه میتواند برای بهبود کارایی و دقت pbg(photoni...

Introduction of the nanoparticles in the bulk glass received a large interest due to their versatile application. The composition of Er+3-doped Zinc-Lead-Phosphate glass samples are prepared by melt-quenching technique. The structural and optical properties of phosphate glass have been examined by x-ray diffraction, fie...

صالحی, حمدا…,

 The electronic structure and optical properties in tetragonal ceramics PbTiO3 are studied by using full-potential linearized augmented plane wave (FP-LAPW) method in density functional theory (DFT) with the generalized gradient approximation (GGA) by WIEN2K package. The theoretical calculated optical properties and energy loss (EEL) spectrum yield a static refractive index of 2.59 and a plasmo...

Journal: :international journal of nano dimension 0
j. nouri department of chemistry, mahabad branch, islamic azad university, mahabad, iran t. khoshravesh department of chemistry, mahabad branch, islamic azad university, mahabad, iran s. khanahmadzadeh department of chemistry, mahabad branch, islamic azad university, mahabad, iran a. salehabadi department of chemistry, naragh branch ,islamic azad university, naragh, iran m. enhessari department of chemistry, naragh branch ,islamic azad university, naragh, iran

li2ni8o10 and limn2o4 nanoparticles as cathode materials of lithium ion battery, were successfully synthesized using lithium acetate, nickel and manganese acetate as li, ni and mn sources and stearic acid as a complexing reagent. the structure of the obtained products were characterized by ft-ir and xrd. the shape, size and distribution of the li2ni8o10 and limn2o4 nanoparticles were observed b...

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...

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