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Spacer Layer (spacer + layer)

Distribution by Scientific Domains
Physics and Astronomy75%

Selected Abstracts

Multilayered Core/Shell Nanowires Displaying Two Distinct Magnetic Switching Events,

ADVANCED MATERIALS, Issue 22 2010
Yuen Tung Chong
Atomic layer deposition (ALD) and electrodeposition are combined with a porous template to create ordered arrays of nanowires in which a nickel core and an iron oxide shell are separated by a silica spacer layer. The switching of each magnetic component is distinct and occurs at a field that depends on the tunable thicknesses of the various layers. [source]

Textured growth and microstructure of pulsed laser deposited Nb/Cr/SmCo5 hybrid structures

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2010
R. Schaarschuch
Abstract Hybrid structures based on superconducting Nb and highly coercive ferromagnetic SmCo5 films grown on MgO(100) substrates were fabricated by pulsed laser deposition under UHV conditions. Thin film architectures of SmCo5 on Nb and the reversed system both with and without Cr spacer layer between superconductor and ferromagnet were examined by transmission electron microscopy and X-ray diffraction concerning their microstructure and epitaxial relationship, respectively. For SmCo5 on Nb with thick intermediate Cr spacer the epitaxial relationship MgO(001)[100]//Cr(001)[110]//Nb(001)[110]//Cr(001)[110]//SmCo5(11,,,20)[0001]//Cr(001)[110] was found. With decreasing thickness of the Cr spacer layer the strength of the texture decreases and finally crystallinity of SmCo5 is lost. In the reversed layer system, Nb on Cr on SmCo5, with decreasing thickness of the Cr spacer layer the epitaxial relationships change from SmCo5(11,,,20)[0001]//Nb(001)[110] to local SmCo5(11,,,20) [0001]//Nb(110)[1,,,11] and the Nb texture changes from the (001)[110] component to a ,110, fibre. The orientation relationships observed are discussed with regard to elastic strain energy minimization. [source]

Spacer layer thickness effects on the photoluminescence properties of InAs/GaAs quantum dot superlattices

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 3 2003
B. Ilahi
Abstract InAs/GaAs vertically stacked self-assembled quantum dot (QD) structures with different GaAs spacer layer thicknesses are grown by solid source molecular beam epitaxy (SSMBE) and investigated by transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy. An increase in the polarization anisotropy is observed when the spacer layer thickness decreases. For a 10 monolayer (ML) thick inter-dots GaAs spacer, the TEM image shows an increase in the QD size when moving to the upper layer accompanied by the generation of dislocations. Consequently, the corresponding temperature-dependant PL properties are found to exhibit an unusual behaviour. The main PL peak is quenched at a temperature around 190 K giving rise to a broad background correlated with the formation of a miniband in the growth direction due to the strong interlayer coupling. For a thicker GaAs spacer layer (30 ML), multilayer QDs align vertically in stacks with no apparent structural defects. Over the whole temperature range, the excitonic band energies are governed by the Varshni empirical relation using InAs bulk parameters and the PL line width shows a slight monotonic increase. For a thinner GaAs interlayer, the thermal activation energies of the carrier emission out of the quantum dots are found to be considerably small (about 25 meV) due to the existence of defects. By combining these structural and optical results, we can conclude that a thinner GaAs spacer has a poorer quality. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Optical properties of InAs/InP quantum dot stack grown by metalorganic chemical vapor deposition

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 4 2003
Heedon Hwang
Abstract The 5-layer InAs quantum dot (QD) stack was grown on an (001) InP substrate by low pressure-metalorganic chemical vapor deposition. 40 nm InP spacer layers were inserted between the InAs QDs. The integrated intensity of the photoluminescence peak at 300 K was over 12% of that at 10 K. Far-infrared absorption peaks were observed at 819 cm,1 (101.64 meV) and 518 cm,1 (64.08 meV) from this structure at room temperature by attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. Raman analysis showed that the peak at 819 cm,1 was attributed to a plasmon related peak in the n-type InP substrate. The absorption peak at 518 cm,1 was regarded as a peak related with intersubband transition in the InAs QDs, suggesting that room temperature operating quantum dot devices may be fabricated. [source]