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Resonance Raman scattering by exciton polaritons in crystals of CuGaS2 under excitation with the 4880 and 4765 Å lines of an Ar+ laser at 9 K is studied. Lines of one-and two-phonon scattering of excitonic polaritons are found and studied. It is shown that the 1LO and 2LO phonons are arranged in accordance with their energies as the Stokes shifts move farther away from the excitation energy. 相似文献
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We demonstrate the controlled preparation of Er‐ and Eu‐doped GaP‐oxide porous composites. The fabrication procedure entails the use of porous semiconductor templates and the impregnation of rare earth ions from a rare earth salt solution in alcohol and thermal treatment. The composites exhibit strong green and red emission that comes from finely dispersed ErPO4 and EuPO4 oxide submicron phases in the composite. These materials may prove useful in future generations of optoelectronic and photonic devices. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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P.C. Ricci R. Corpino M. Marceddu I.M. Tiginyanu 《Journal of Physics and Chemistry of Solids》2005,66(11):1950-1953
The Silver Gallium Sulfide (AgGaS2) ternary compound is a wide bandgap semiconductor (about 2.7 eV) whose photoluminescence properties are characterized by excitons and donor-acceptor pairs recombinations. We have performed photoluminescence (PL) measurement exciting with the third harmonic (3.5 eV) of a Nd:YAG laser from room temperature down to 10 K at different excitation power. In this work we report the dependence of the ‘green band’ on the excitation power at various temperatures. 相似文献
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V. M. Markushev V. V. Ursaki M. V. Ryzhkov C. M. Briskina I. M. Tiginyanu E. V. Rusu A. A. Zakhidov 《Applied physics. B, Lasers and optics》2008,93(1):231-238
A ZnO structure in the form of a core–shell wire was grown with a modified vapour transport and condensation method. The wire
consists of a dense core which may play the role of a waveguide and a shell formed mainly from tetrapod-type crystallites.
The high optical quality of the produced ZnO material is confirmed by continuous wave photoluminescence (PL) analysis demonstrating
that low- temperature PL is related to the recombination of bound excitons, while room-temperature PL is due to free excitons.
Good quality of the crystal structure is demonstrated also by the Raman spectrum. The shell of the wire exhibits room-temperature
laser action due to lasing modes in tetrapods under the excitation by nanosecond laser pulses. The nature of the lasing modes
is discussed. A simplified model for one of the possible modes is suggested. 相似文献
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A. I. Dikusar P. G. Globa O. O. Redkozubova S. P. Sidelinikova L. Sirbu I. M. Tiginyanu 《Russian Journal of Electrochemistry》2006,42(12):1298-1303
Problems, associated with electrochemical dimensional treatment and chemical deposition as methods of manufacturing nanocomposites based on the AIIIBV semiconductors, are considered by studying indium phosphide (n-InP). The results of manufacturing nanocomposites Cu-n-InP and Ag-n-InP by chemical deposition of copper and silver into pores produced by electrochemical anodic dissolution are described. The metallization kinetics and peculiarities of metal distribution inside nanopores at large values of A are described (A = h/d is a geometrical factor or an aspect ratio, where h and d are the pore’s depth and diameter). It is shown that the degree of the nanopores’ filling is defined by the chemical deposition rate. A relatively high copper deposition rate pertaining to the manufacturing of Cu-n-InP leads to a low throwing power of electrolyte and, as a consequence, to a low level of the pores’ filling. Conversely, the substantially lower rate of the silver chemical deposition from a triethanolamine-containing solution leads to a better uniformness of deposition and to the reaching of conditions conducive to a higher degree of the pores’ filling with metal. 相似文献
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Self‐organized quasi‐ordered two‐dimensional hexagonal arrays of pores with diameters as low as 70 nm in n‐InP substrates subjected to anodic etching in aqueous solution of NaCl are reported. We show that proper periodic modulation of the applied potential with time allows one to reach 3D nanostructuring of the material. Anodization in salty water proves to be a cost‐effective and environmentally‐friendly tool for spatial nanostructuring of materials and nonlithographic manufacturing of semiconductor nanotemplates for nanofabrication. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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V. V. Sergentu I. M. Tiginyanu V. V. Ursaki M. Enachi S. P. Albu P. Schmuki 《固体物理学:研究快报》2008,2(5):242-244
We propose to assemble negative index materials (NIMs) from dielectric nanotubes with inner and outer surfaces covered by thin metallic films. The focusing properties of flat and concave lenses assembled from metallized titania nanotubes are compared with those of lenses made from nanorods with the refractive index n = –1 by performing numerical calculations using a multiple‐scattering approach. Focusing is proved for both types of lenses, however, the focusing properties of concave lenses are better. The lenses are shown to be tolerant to the introduction of disorder in the arrangement of nanotubes. Moreover, the disorder proves to improve the quality of the focal spot. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献