نتایج جستجو برای: photoluminescence

تعداد نتایج: 11123  

2011
Zülbiye ÖNAL Hüseyin ZENGİN Mehmet SÖNMEZ

This research concentrates on the preparation, characterization, and photoluminescence properties of new Co(II), Ni(II), Cu(II), and Zn(II) complexes of N-aminopyrimidine-2-thione. The ligand and metal complexes were characterized by elemental analysis and spectroscopic studies such as IR, UV/Vis, API-ES, NMR, fluorescence, and magnetic susceptibility measurements. The ligand and the resulting ...

Journal: :Nano letters 2007
Hao Huang August Dorn Gautham P Nair Vladimir Bulović Moungi G Bawendi

We demonstrate reversible quenching of the photoluminescence from single CdSe/ZnS colloidal quantum dots embedded in thin films of the molecular organic semiconductor N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine (TPD) in a layered device structure. Our analysis, based on current and charge carrier density, points toward field ionization as the dominant photoluminescence q...

Journal: :Nature nanotechnology 2008
S Godefroo M Hayne M Jivanescu A Stesmans M Zacharias O I Lebedev G Van Tendeloo V V Moshchalkov

Silicon dominates the electronics industry, but its poor optical properties mean that III-V compound semiconductors are preferred for photonics applications. Photoluminescence at visible wavelengths was observed from porous Si at room temperature in 1990, but the origin of these photons (do they arise from highly localized defect states or quantum confinement effects?) has been the subject of i...

2005
Y. Gu Igor L. Kuskovsky M. van der Voort G. F. Neumark X. Zhou M. C. Tamargo

Detailed studies with spectral and time-resolved photoluminescence, photoluminescence excitation, and absorption spectroscopies show the formation of type-II quantum structures squantum dotsd in a Zn-Se-Te multilayer system with submonolayer quantities of Te. Moreover, it is shown that in addition to these quantum dots, Te isoelectronic centers are also present in the same material system and c...

2007
C. TSAI K.-H. LI

The effects of illumination during anodic etching of porous Si have been studied. For a fixed current density and anodization time, it has been observed that below a critical irradiance level, increasing the radiant flux density during anodization results in higher photoluminescence and a blue shift of the photoluminescence spectra. For irradiance above the critical value, the photoluminescence...

2011
S. P. Puppalwar S. J. Dhoble Gajendra Singh Animesh Kumar

Using a simple combustion process, rare earth doped novel compounds like fluorides LiBF4 and Li3BF6 can be prepared. Combustion synthesis furnishes a quick method for preparation of these phosphors. The prepared phosphors were characterized by the photoluminescence (PL) techniques. It is suggested that borofluoride based materials can be developed as low-cost phosphors. Formation of single phas...

Journal: :ACS nano 2015
Michael E Turk Patrick M Vora Aaron T Fafarman Benjamin T Diroll Christopher B Murray Cherie R Kagan James M Kikkawa

We use time-integrated and time-resolved photoluminescence and absorption to characterize the low-temperature optical properties of CdSe quantum dot solids after exchanging native aliphatic ligands for thiocyanate and subsequent thermal annealing. In contrast to trends established at room temperature, our data show that at low temperature the band-edge absorptive bleach is dominated by 1S3/2h h...

2017
Jean-Philippe Gauthier Cédric Robert Samy Almosni Yoan Léger Mathieu Perrin Jacky Even Andrea Balocchi Hélène Carrère Xavier Marie Charles Cornet J.-P. Gauthier C. Robert S. Almosni Y. Léger

We report on the structural and optical properties of (In,Ga)AsN self-assembled quantum dots grown on GaP (001) substrate. A comparison with nitrogen free (In,Ga)As system is presented, showing a clear modification of growth mechanisms and a significant shift of the photoluminescence spectrum. Low temperature carrier recombination dynamics is studied by time-resolved photoluminescence, highligh...

Journal: :Physical review letters 2006
Y D Jho Xiaoming Wang J Kono D H Reitze X Wei A A Belyanin V V Kocharovsky Vl V Kocharovsky G S Solomon

We investigate photoluminescence from a high-density electron-hole plasma in semiconductor quantum wells created via intense femtosecond excitation in a strong perpendicular magnetic field, a fully quantized and tunable system. At a critical magnetic field strength and excitation fluence, we observe a clear transition in the band-edge photoluminescence from omnidirectional output to a randomly ...

2012
D. E. Wohlert S. T. Chou A. C. Chen K. Y. Cheng

Related Articles Deep traps and enhanced photoluminescence efficiency in nonpolar a-GaN/InGaN quantum well structures J. Appl. Phys. 111, 033103 (2012) Deep traps in nonpolar m-plane GaN grown by ammonia-based molecular beam epitaxy Appl. Phys. Lett. 100, 052114 (2012) Growth and photoluminescence of self-catalyzed GaP/GaNP core/shell nanowires on Si(111) by gas source molecular beam epitaxy Ap...

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