Materials Literature
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We study the excitonic structure of CdSe/ZnSe self assembled quantum dots (SAQD) by magneto-photoluminescence (PL) spectroscopy. Using fixed 200 nm apertures through a metal film, we are able to probe single narrow (200 micro-eV) spectroscopic lines emitted from CdSe quantum dots at 2K. Using linear polarization analy…
A field-effect transistor has been constructed that employs a perovskite-type SrTiO3 single crystal as the semiconducting channel. This device functions as an n-type accumulation-mode device. The device was fabricated at room temperature by sputter-deposition of amorphous Al2O3 films as a gate insulator on the SrTiO3…
The shape of the absorbance edge for a suspension of semiconductor quantum particles is influenced both by the electronic transition and the distribution of band gaps in the system. Using a suitable model to relate the absorption energy to the particle radius, we demonstrate this relationship by inferring the particle…
Light-emitting silicon nanocrystals embedded in ${\mathrm{SiO}}_{2}$ have been investigated by x-ray absorption measurements in total electron and photoluminescence yields, by energy filtered transmission electron microscopy and by ab initio total energy calculations. Both experimental and theoretical results show tha…
Being composed of crystalline lamellae and entangled amorphous polymeric chains in between, semicrystalline polymers always show a complicated deformation behavior under tensile deformation. In recent years, the process of tensile deformation was found to exhibit several regimes: intralamellar slipping of crystalline…
Single-source molecular precursors were used to synthesize II-VI compound semiconductor nanowires for the first time. Cadmium sulfide and zinc sulfide nanowires were prepared using cadmium diethyldithiocarbamate, Cd(S2CNEt2)2, and zinc diethyldithiocarbamate, Zn(S2CNEt2)2, respectively, as precursors in a gold nanoclu…
Highly transparent conductive, aluminum-doped zinc oxide (ZnO:Al) films were deposited on glass substrates by midfrequency magnetron sputtering of metallic aluminum-doped zinc target. ZnO:Al films with surface work functions between 3.7 and 4.4 eV were obtained by varying the sputtering conditions. Organic light-emitt…
A large quantity of nanosized ZnO tubular structures was prepared using a very simple thermal evaporation of mixed Zn–ZnO powders under a wet oxidation condition. The ZnO nanotubes have a hollow core with crystalline wall of 8–20 nm in thickness. Optical properties of ZnO nanotubes were studied at room temperature. Ra…
Type-II band engineered quantum dots (CdTe/CdSe(core/shell) and CdSe/ZnTe(core/shell) heterostructures) are described. The optical properties of these type-II quantum dots are studied in parallel with their type-I counterparts. We demonstrate that the spatial distribution of carriers can be controlled within the type-…
A high-resolution x-ray photoelectron spectroscopy (HRXPS) study of the Ni $3s$ core level is presented. Ni $3s$ HRXPS spectra were compared at $T=298\mathrm{K}$ ${(T=0.47T}_{c})$ and 863 K ${(T=1.37T}_{c}).$ No significant variation with temperature is observed. These HRXPS results, combined with prior spin-resolved…
Abstract After synthesizing two chromophores with imine, we prepared acrylic nonlinear optical (NLO) polymers that contained the chromophores for all‐optical wavelength converters in optical fiber communication. The polymers show high d 33 , 35 pm · V −1 , at 1.55 μm (pumping beam), considering their low losses, −3.0…
Abstract Number‐ and weight‐average molecular weight of condensation polymers formed by primary molecules carrying different species of functional groups {A i } (i = 1, 2, …, s) are derived by cascade theory. These functional groups are allowed to form multiple junctions of variable multiplicity k . The gel point cond…
Abstract 3,3′‐Dinitrobenzidine was first reacted with excess m ‐chlorophenyl acid to form a monomer with dicarboxylic acid end groups. Two types of aromatic dianhydrides (Pyromellitic diconhydride (PMDA) and 3,3′,4,4′‐sulfonyl diphthalic anhydride) were also reacted with excess 4,4′‐diphenylmethane diisocyanate to for…
When producing (pressing) flax/PP composite panels, several processing parameters have to be considered. This paper describes how these parameters affect some properties of the resulting panel. The multidirectional flax/PP composite panels were made from needle-punched hybrid nonwovens. First the most appropriate proc…
Abstract The varying degree of preferential orientation observed in films of poly(alkylthiophene)s obtained by solution casting from different solvents has been studied quantitatively with X‐ray diffraction. The (uniaxial) orientational distribution function is obtained after some important instrumental corrections th…
The maximum of the color-conferring charge-transfer (CT) band in Prussian Blue (PB) varies with the electrochemically introduced cation M(z+) incorporated (as "supernumerary") for charge neutrality, and the dependence on particular properties of the M(z+) has been sought. With alkali-metal ions, the CT-maximum shifts…
We report results obtained from Monte Carlo simulations investigating mesophase formation in two model systems of hard pear-shaped particles. The first model considered is a hard variant of the truncated Stone-expansion model previously shown to form nematic and smectic mesophases when embedded within a 12-6 Gay-Berne…
The syntheses of two distinctive types of indium complex derived from trimethylindium (InMe(3)) are reported. The first kind has a generalized structural formula [InMe(2)(amak)](2), where (amak)H is an abbreviation for a series of chelating amino alcohol ligands HOC(CF(3))(2)CH(2)NHR, R = (CH(2))(2)OMe (1), Me (2), an…
Computer modeling techniques, which were employed to investigate the effect of water on the reactivity and stability of a SiO 2 nanotube, show that the side of the nanotube is relatively resistant to dissociative chemisorption and silicon dissolution but that the end of the nanotube is highly reactive toward water and…
Azamethine dyes of the merocyanine type [4-(N,N-di-n-butylamino)-2-methylphenyl][2,4-di-keto-3-[N'-(n-hexyl)]-5-cyano-6-methyl-3-pyridinio]-1-azamethine (1) and [4-(N,N-diethylamino)-2-(N'-tert-butylcarboxy)-amidophenyl]-[2,4-diketo-3-[N"-(n-hexyl)]-5-cyano-6-methyl-3-pyridinio]-1-azamethine (2) have been used as surf…