Materials Literature
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We study spin dynamics of excitons confined in self-assembled CdSe quantum dots by means of optical orientation in magnetic field. At zero field the exciton emission from QDs populated via LO phonon-assisted absorption shows a circular polarization of 14%. The polarization degree of the excitonic emission increases dr…
We propose materials design to fabricate a new class of diluted magnetic semiconductors (DMSs) based on MgO, SrO and BaO without magnetic elements. Replacing the oxygen atoms by other atoms such as C atoms leads to the induction of a deep-impurity band. These materials show ferromagnetic behaviour if the impurity-band…
The interparticle distance has been systematically varied by controlling the concentration of 8-nm CoFe 2 O 4 or MnFe 2 O 4 spinel ferrite nanocrystals dispersed in eicosane. For both nanoparticulate systems, the blocking temperature decreased with increasing interparticle distance through dilution of nanocrystals, wh…
High performance pseudocapacitive characteristics of potentiodynamically deposited NiO are reported here. Three-dimensional nanowhiskers of NiO were prepared by potentiodynamically depositing nickel hydroxide on stainless steel (SS) and heating the hydroxide in air at 300°C for 3h. The scan rate used for the depositio…
We report the scaling behavior of 1∕f noise in single-walled carbon nanotube devices. In this study we use two-dimensional carbon nanotube networks to explore the geometric scaling of 1∕f noise and find that for devices of a given resistance the noise scales inversely with device size. We have established an empirical…
This paper aims to explain the size-effect in the Primary Deformation Zone (PDZ) in machining using strain gradient plasticity theory. Considering a parallel-sided shear zone configuration, models are formulated for the evaluation of strain gradient, density of geometrically necessary dislocations, shear strength and…
We have studied the interactions in the solid phase between a blue-light-emitting organic conjugated polymer {poly[(9,9-dihexylfluorenyl-2,7-diyl)-alt-co-(9,ethyl-3,6-carbazole)]} and colloidal CdSe∕ZnS core shell quantum dots. We demonstrate by time resolved photoluminescence measurements that efficient Förster energ…
We report the synthesis and characterization of ferroelectric lead zirconate titanate Pb(Zr0.53Ti0.47)O3 (PZT) nanowires. The PZT nanowires, with diameters of about 45nm and lengths of about 6μm, were fabricated by means of a sol-gel method utilizing nanochannel alumina templates. After postannealing at 700°C, the PZT…
Biodegradable nanocomposites were successfully fabricated from cellulose acetate (CA) plasticized with triethyl citrate (TEC), and combined with Cloisite 30B organoclay, using maleic anhydride grafted cellulose acetate butyrate (CAB- g -MA) as the compatibilizer. The nanostructure of the nanocomposites was investigate…
The formation of pure single crystalline silicon nanoparticles by microwave induced decomposition of silane in a low pressure flow reactor is reported. The morphology and crystal structure of the particles are characterized in situ by particle mass spectrometry (PMS) and ex situ by means of X-ray diffraction, high res…
We study ground state properties of the double-exchange model on triangle chain in the classical limit on $t_{2g}$ spins. The ground state is determined by a competition among the kinetic energy of the $e_g$ electron, the antiferromagnetic exchange energy between the $t_{2g}$ spins, and frustration due to a geometric…
Absolute negative refraction regions for both polarizations of electromagnetic wave in two-dimensional photonic crystal have been found through both the analysis and the exact numerical simulation. Especially, absolute all-angle negative refraction for both polarizations has also been demonstrated. Thus, the focusing…
We present a tight-binding based GW approach for the calculation of quasiparticle energy levels in confined systems such as molecules. Key quantities in the GW formalism like the microscopic dielectric function or the screened Coulomb interaction are expressed in a minimal basis of spherically averaged atomic orbitals…
We present a theoretical formulation of the one-electron problem constrained on the surface of a cylindrical tubule with varying diameter. Because of the cylindrical symmetry, we may reduce the problem to a one-dimensional equation for each angular momentum quantum number $m$ along the cylindrical axis. The geometrica…
Anharmonicity of the interatomic potential is taken into account for the quantitative simulation of the conduction and valence band offsets for strained semiconductor heterostructures. The anharmonicity leads to a weaker compressive hydrostatic strain than that obtained with the commonly used quasiharmonic approximati…
Abstract To avoid the complex core surface functionalization or pretreatment that is necessary in order to coat latex and silica colloids with a uniform, complete metal shell, the solvent‐assisted route has been explored to prepare a complete metal (Ag or Au) shell with controlled thickness on polystyrene (PS) colloid…
Abstract It is thought that morphologies of bacterial carbonates can be used to identify microbial fossils and/or precipitates in sediments and rocks. This study shows that calcite and vaterite formed in a gel medium in the presence of Myxococcus xanthus display a range of morphologies that depend on whether the bacte…
The Peierls stress of the a/2⟨110⟩ screw dislocation belonging to the shuffle set is calculated for silicon using density functional theory. We have checked the effect of boundary conditions by using two models, the supercell method where one considers a periodic array of dislocations, and the cluster method where a s…
The diffusion length of minority carriers L p,n is an important characterisation parameter in semiconductor materials and is of particular interest when constructing devices such as solar cells (Hovel 1975), double hetero junction lasers (Casey and Panish 1978) and bipolar transistors. Their efficiency depends primari…
An ab initio pseudopotential calculation using density functional theory within the local density approximation has been performed to investigate the electronic properties of TlSe, which is of chainlike crystal geometry. The energy bands and effective masses along high symmetry directions, the density of states, and v…