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Phonon Replicas (phonon + replica)

Distribution by Scientific Domains
Physics and Astronomy100%

Selected Abstracts

Optical and magnetic properties of c -oriented ZnCoO films

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 11 2006
Huijuan Zhou
Abstract We investigated ZnCoO thin films prepared via sol-gel methods and dip-coating techniques. The Co concentrations range from 0.5% to 5%. The films show the wurtzite crystal structure of ZnO and are highly c -axis oriented grown on the quartz substrates. They have a typical grain size of 20 to 50 nm and a thickness between 300 nm and 1 µm. The fine structures of the Co (3d7) internal absorptions are well resolved, all zero-phonon lines (ZPL) and phonon replica related to the 4T1(F) , 4A2 are observed, demonstrating the good crystalline quality of the layers and the incorporation of the Co2+ on Zn2+ lattice sites. The films show paramagnetic behaviour. (© 2006 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]

Role of excitons in the excitation of deep-level emission in ZnO crystals

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2010
V. I. Kushnirenko
Abstract In undoped ZnO crystals, photoluminescence excitation (PLE) spectra of deep-level green and orange PL bands as well as photocurrent (PC) spectra were measured at 77 and 290 K. Some PLE and PC peaks whose energy positions coincided with that of free exciton and its excited states were observed, the intensity of PL and PC excited in these peaks being higher than under excitation by band-to-band light. At the same time, a sharp minimum was found in PLE and PC spectra at the position of donor-bound exciton. Obtained results were accounted for by the interaction of excitons with lattice defects. A number of longer wavelength PLE and PC peaks whose energy positions coincided in fact with that of the first, second and third phonon replicas of free exciton were also observed. The origin of these peaks is discussed. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Luminescence and energy structure of ultrathin InAs/AlAs quantum wells

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2008
T. S. Shamirzaev
Abstract The energy spectrum of thin InAs/AlAs quantum wells (QWs) has been studied by photoluminescence (PL). It has been found that the PL spectra of the QWs consist of intense lines related to a no-phonon excitonic transition accompanied with its phonon replicas. The band alignment in the QWs with the lowest conduction band states belonging to the indirect minimum is shown to be of type I. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Energy relaxation in CdSe/ZnSe quantum dots under the strong exciton-phonon coupling regime

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 4 2006
A. V. Platonov
Abstract Resonant photoluminescence and photoluminescence excitation spectroscopy have been applied to CdSe/ZnSe quantumdots where separation between the quantized levels is close to the optical phonon energy. Astrong relaxation enhancement induced by the optical phonon is observed. The fine structure of the phonon replicas is resolved. It is attributed to the optical phonons with large wave vectors from the symmetrical points of the Brillouin zone. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]