نتایج جستجو برای: photoluminescence pl

تعداد نتایج: 21930  

2003
Y. Gu Igor L. Kuskovsky G. F. Neumark X. Zhou O. Maksimov S. P. Guo M. C. Tamargo

We present photoluminescence (PL) studies of Cl-doped Zn1 xBexSe (x 1⁄4 0–0.029) alloys performed in wide ranges of temperature (10–296 K) and of excitation intensities. We show that the high-temperature PL is characterized by a free-to-acceptor-type transition, involving shallow state of the localized holes. We shall show that similar transitions are also present in comparable undoped samples,...

Journal: :Nanotechnology 2010
M H Sun E S P Leong A H Chin C Z Ning G E Cirlin Yu B Samsonenko V G Dubrovskii L Chuang C Chang-Hasnain

We report the first photoluminescence (PL) characterization of InAs nanowires (NWs). The InAs NWs were grown on GaAs(111) B and Si(111) substrates using the Au-assisted molecular beam epitaxy (MBE) growth technique or metal-organic chemical vapor deposition (MOCVD). We compared the PL response of four samples grown under different conditions using MBE or MOCVD. High-resolution transmission elec...

Journal: :Physical review letters 2004
Jonathan Keeling L S Levitov P B Littlewood

Recent experiments on two-dimensional exciton systems have shown that excitons collect in shallow in-plane traps. We find that Bose condensation in a trap results in a dramatic change of the exciton photoluminescence (PL) angular distribution. The long-range coherence of the condensed state gives rise to a sharply focused peak of radiation in the direction normal to the plane. By comparing the ...

2016
Tomohiro Shiraki Tomonari Shiraishi Gergely Juhász Naotoshi Nakashima

Single-walled carbon nanotubes (SWNTs) show unique photoluminescence (PL) in the near-infrared (NIR) region. Here we propose a concept based on the proximal modification in local covalent functionalization of SWNTs. Quantum mechanical simulations reveal that the SWNT band gap changes specifically based on the proximal doped-site design. Thus, we synthesize newly-designed bisdiazonium molecules ...

2012
Clemens Simbrunner Gerardo Hernandez-Sosa Francesco Quochi Günther Schwabegger Chiara Botta Martin Oehzelt Ingo Salzmann Tatjana Djuric Alfred Neuhold Roland Resel Michele Saba Andrea Mura Giovanni Bongiovanni Antje Vollmer Norbert Koch Helmut Sitter

We report on the epitaxial growth of periodic para-hexaphenyl (p-6P)/α-sexi-thiophene (6T) multilayer heterostructures on top of p-6P nanotemplates. By the chosen approach, 6T molecules are forced to align parallel to the p-6P template molecules, which yields highly polarized photoluminescence (PL)-emission of both species. The PL spectra show that the fabricated multilayer structures provide o...

2012
Sandra Herlufsen Daniel Macdonald Karsten Bothe Jan Schmidt

We report on measurements of the interstitial iron concentration in boron-doped crystalline silicon by measuring the dissociation rate of iron-boron pairs using a camera-based photoluminescence setup (dynamic Fei imaging). This approach enables us to identify the interstitial iron concentration without measuring absolute values of the carrier lifetime and without knowing the recombination prope...

2017
Igor Ozerov Dimitri Nelson Alexander Bulgakov Wladimir Marine Marc Sentis I. Ozerov D. Nelson A. V. Bulgakov M. Sentis

We present the results of experiments on synthesis of ZnO nanoclusters by reactive pulsed laser deposition (PLD). The nanoclusters were formed and crystallized in the gas phase and deposited on SiO2 substrates. The nanostructured films were characterized by conventional photoluminescence (PL). The PL spectra consist of a narrow UV excitonic band and a broad visible band related to defects in th...

2016
S. Bangaru

The comparison of Optical absorption, Photoluminescence (PL), Thermoluminescence (TL) and other optical studies of X-ray irradiated Ce 3+ doped KBr and KI single crystals were discussed. Photoluminescence of these crystals exhibits characteristic Ce 3+ emission due to 5d-4f transition in both the studied material in addition to the host emission. Optical absorption and PL studies confirm the pr...

D. Ghanbari M. Ranjbar M. Salavati-Niasari,

ZnS  nanoparticles  were  synthesized  via  a  simple  surfactant  free microwave  route.  In  this  synthesis, thioacetamide  was  used  as sulfur  source.  The effects  of different  parameters  such  as  type of zinc precursor,  time  and  power  of  irradiation  on  the  morphology and  particle  size  of  the  products  have been  investigated.  The nanostructures  were  characterized  by ...

Journal: :Chemical science 2012
Andrew B Greytak Peter M Allen Wenhao Liu Jing Zhao Elizabeth R Young Zoran Popović Brian Walker Daniel G Nocera Moungi G Bawendi

We report single-particle photoluminescence (PL) intermittency (blinking) with high on-time fractions in colloidal CdSe quantum dots (QD) with conformal CdS shells of 1.4 nm thickness, equivalent to approximately 4 CdS monolayers. All QDs observed displayed on-time fractions > 60% with the majority > 80%. The high-on-time-fraction blinking is accompanied by fluorescence quantum yields (QY) clos...

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