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Temperature Photoluminescence (temperature + photoluminescence)

Distribution by Scientific Domains

Physics and Astronomy	80%

Selected Abstracts

Room temperature photoluminescence of the Li2ZnTi3O8 spinel: Experimental and theoretical study

INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 5 2005
M. S. C. Câmara
Abstract This article describes the characterization of intense photoluminescence observed at room temperature of the Li2ZnTi3O8 spinel phase, obtained by the polymeric precursor method. The evolution of visible photoluminescence is demonstrated by measurement of the photoluminescence signal as a function of the annealing treatment time. The evolution indicates that PL can be attributed to the presence of an inorganic disordered phase. In addition, increased annealing treatment times cause not only a decrease in the total residual content of organic material in the samples, but also an intensified photoluminescence. We discuss the nature of visible photoluminescence at room temperature of the Li2ZnTi3O8 spinel phase in the light of results of both recent experimental and quantum mechanical theoretical studies. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005 [source]

Photoluminescence properties of GaAs nanowire ensembles with zincblende and wurtzite crystal structure

PHYSICA STATUS SOLIDI - RAPID RESEARCH LETTERS, Issue 7 2010
B. V. Novikov
Abstract Self-standing III,V nanowires (NWs) are promising building blocks for future optoelectronic devices such as LEDs, lasers, photodetectors and solar cells. In this work, we present the results of low temperature photoluminescence (PL) characterization of GaAs NWs grown by Au-assisted molecular beam epitaxy (MBE), coupled with the transmission electron microscopy (TEM) structural analysis. PL spectra contain exci- ton peaks from zincblende (ZB) and wurtzite (WZ) crystal structures of GaAs. The peaks are influenced by the quantum confinement effects. PL bands corresponding to the exciton emission from ZB and WZ crystal phases are identified, relating to the PL peaks at 1.519 eV and 1.478 eV, respectively. The obtained red shift of 41 meV for WZ GaAs should persist in thin NWs as well as in bulk materials. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Light emitting diodes on silicon substrates: preliminary results

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 10 2009
Alexandre Bondi
Abstract III-V quantum wells (QW) superlattices have been grown by molecular beam epitaxy on GaP substrates for photonics applications on silicon. We first present room temperature photoluminescence (PL) results for GaAsP/GaP QWs. A detailed analysis of low temperature PL experiments is then performed. QW contribution is pointed out, and the structuration of the QW emission is attributed to LA phonon replica. A comparison with electronic bandstructure is performed, and a discussion is proposed on the nature of the observed transition (direct or indirect). Finally, it is shown that these QWs can be used as active zone in light emitters on silicon. Growth of good quality GaP epilayers on silicon is also presented. The crystalline quality of the deposited GaP near the GaP/Si interface is studied by Raman spectroscopy. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Photoluminescence and TEM characterization of (AlyGa1,y)1,xInxP layers grown on graded buffers

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 4 2007
J. Novak
Abstract Composition, crystallographic quality and low temperature photoluminescence of AlGaInP quaternary layers were studied. These layers were grown on the InGaP/GaP graded buffers by metalorganic vapour phase epitaxy. Final composition of the graded buffer top layer was xIn = 0.24. Incorporation of the small amount Al into quaternary led to a substantial improvement of the surface morpohology and crystallographic quality observed in cross-sectional TEM view. Incorporation of higher amount of Al (above 1%) led to the increase of lattice mismatch, decrease of In content in the alloy and to the indirect band gap. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

1.3 µm high indium content (42.5%) GaInNAs/GaAs quantum wells grown by molecular beam epitaxy

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3 2006
Zhichuan Niu
Abstract High structural and optical quality 1.3 µm GaInNAs /GaAs quantum well (QW) samples with 42.5% indium content were successfully grown by molecular beam epitaxy. The growth of well layers was monitored by reflection high-energy electron diffraction (RHEED). Room temperature photoluminescence (PL) peak intensity of the GaIn0.425NAs/GaAs (6 nm/20 nm) 3QW is higher than, and the full width at half maximum (FWHM) is comparable to, that of In0.425GaAs/GaAs 3QW, indicating improved optical quality due to strain compensation effects by introducing N to the high indium content InGaAs epilayer. The measured (004) X-ray rocking curve shows clear satellite peaks and Pendellösung fringes, suggesting high film uniformity and smooth interfaces. The cross sectional TEM measurements further reveal that there are no structural defects in such high indium content QWs. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]