Monolayers of PbSe and PbS quantum dots and PbSe/CdSe core/shell quantum dots made by Langmuir–Blodgett deposition are compared, with a focus on the formation, the morphology and the photoluminescence properties of the films.
Posts Tagged ‘formation’
Langmuir–Blodgett monolayers of colloidal lead chalcogenide quantum dots: morphology and photoluminescence
Posted by admin on July 5th, 2010
Posted in Nanotechnology 
Tags: around-the-pbse, formation, Photoluminescence, resulting, resulting-films 
Comments OffNanotwinned gold nanowires obtained by chemical synthesis
Posted by admin on June 28th, 2010
We demonstrate a facile method for synthesizing and isolating Au nanowires with a high density of twin boundary defects normal to the growth axis. In this process, oleylamine conveniently plays the role of the solvent, the reducing agent and the ligand
Posted in Nanotechnology Tags: formation, metal-nanowires, Nanowires, pentagonal, plays-the-role, reducing, sharp-contrast, the-nanowires, twin, twin-boundary Comments OffInP and InAs nanowires hetero- and homojunctions: energetic stability and electronic properties
Posted by admin on June 18th, 2010
We performed an ab initio total energy investigation, within the density functional theory, of the energetic stability and the electronic properties of hydrogenated InAs/InP nanowire (NW) heterojunctions, as well as InAs and InP homojunctions composed of different structural arrangements, zinc-blend (zb) and wurtzite (w). For InAs/InP NW heterojunctions our results indicate that w and zb NW heterojunctions are quite similar, energetically, for thin NWs. We also examined the robustness of the abrupt interface through an atomic ##IMG## [http://ej.iop.org/images/0957-4484/21/28/285204/nano352868ieqn1.gif] {mathrm {As}leftrightarrow mathrm {P}} swap at the InAs/InP interface
Posted in Nanotechnology Tags: band-alignment, Electronic, energetic, Energy, energy-barrier, formation, our-results, Results, results-support, the-electronic, the-energetic, the-robustness, well-as-inas Comments OffSurface engineering of quantum dots for in vivo imaging
Posted by admin on June 18th, 2010
The aim of this study was to investigate the effect of gluconic acid (GA) conjugation on the biodistribution of cysteamine-capped quantum dots (amino-QDots) in vivo . Cadmium selenide/zinc sulfide (CdSe/ZnS) was capped with cysteamine through a thiol exchange method, and different amounts of GA were conjugated to the amine groups of cysteamine via the formation of an amide bond. The emission maxima of the synthesized QDots, the amino-QDots and the GA-conjugated amine-QDots (GA-QDots) were located at 720, 600 and 610 nm, respectively
Posted in Nanotechnology Tags: amino, biodistribution, conjugation, cysteamine-via, cytotoxicity, formation, gluconic-acid, located-at-720, Study, synthesized, the-conjugation, the-formation, the-synthesized, thiol-exchange Comments OffControl of magnetization reversal by combining shape and magnetocrystalline anisotropy in epitaxial Fe planar nanowires
Posted by admin on May 28th, 2010
This work presents an analysis of the in-plane magnetization reversal mechanisms of Fe nanowires, with widths from 100 nm to1 µm, fabricated in epitaxial Au(001)/Fe(001)/MgO(001) thin films by means of focused ion and electron beam lithographies, with either positive or negative resist. The experimental results show that the switching mechanisms and hysteresis are almost exclusively functions of the dimensions of the wires and of the Fe intrinsic properties, with minor influence of the specific fabrication route employed upon optimization of nanostructure parameters in terms of crystallinity and morphology, and well defined and reproducible geometry.
Posted in Nanotechnology Tags: Applied, applied-field, behaviour, Dimensions, even-at-high, formation, pinning-at-low, positive, route-employed, structures-even, switching, Wires, work-presents No Comments »0g apparatus to test variable acceleration on nanotube formation
Posted by admin on May 25th, 2010
Posted in Nanotechnology Tags: acceleration, apparatus, formation, Nanotube, Test, variable 6 Comments »In situ analysis of strain relaxation during catalyst-free nucleation and growth of GaN nanowires
Posted by admin on May 21st, 2010
Strain relaxation mechanisms occurring during self-induced growth of nitride nanowires are investigated by in situ reflection high-energy electron diffraction and ex situ high-resolution transmission electron microscopy. Epitaxial GaN nanowires nucleate on an AlN buffer layer under highly nitrogen-rich conditions via the initial formation of coherently strained three-dimensional islands according to the Volmer–Weber growth mechanism. The epitaxial strain relief in these islands occurs by two different processes.
Optimization of photoluminescence of Y 2 O 3 :Eu and Gd 2 O 3 :Eu phosphors synthesized by thermolysis of 2,4-pentanedione complexes
Posted by admin on May 21st, 2010
Spherical shaped nanoparticles of series Y 2 − x Eu x O 3 ( x = 0.06, 0.10, 0.20, and 2) and Gd 2 − x Eu x O 3 ( x = 0.06, 0.10) were prepared by thermolysis of 2,4-pentanedione complexes of Y, Gd, and Eu. The bixbyite phase of Gd 2 − x Eu x O 3 samples was formed at 500 °C, whereas the thermal decomposition of Y and Eu complexes’ mixtures occurred at higher temperatures.
Compensation mechanism in N-doped ZnO nanowires
Posted by admin on May 21st, 2010
N-doped ZnO nanowires are synthesized at a relatively low growth temperature of 500 °C by directly heating zinc powder using NH 3 as the dopant. The incorporation of N into the ZnO nanowires is experimentally confirmed by x-ray photoelectron spectroscopy, Raman spectra and photoluminescence measurements. By combining post annealing experiments after growth with first-principles calculations, the detailed migration mechanism of N and compensation mechanism in N-doped ZnO nanowires are systematically studied
Posted in Nanotechnology Tags: after-growth, Challenge, combining-post, detailed, dopant, formation, Future, getting-p-type, larger-aspect, the-detailed, the-formation No Comments »