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1,651 results on '"Patriarche G"'

351. Growth-interruption-induced low-density InAs quantum dots on GaAs

Author

Li, L., Chauvin, N.J.G., Patriarche, G., Alloing, B., Fiore, A., Li, L., Chauvin, N.J.G., Patriarche, G., Alloing, B., and Fiore, A.

Abstract

We investigate the use of growth interruption to obtain low-density InAs quantum dots (QDs) on GaAs. The process was realized by Ostwald-type ripening of a thin InAs layer. It was found that the optical properties of the QDs as a function of growth interruption strongly depend on InAs growth rate. By using this approach, a low density of QDs (4 dots/ µm2) with uniform size distribution was achieved. As compared to QDs grown without growth interruption, a larger energy separation between the QD confined levels was observed, suggesting a situation closer to the ideal zero-dimensional system. Combining with an InGaAs capping layer such as In-rich QDs enable 1.3 µm emission at 4 K.

Published
2008

352. Photoluminescence from a single InGaAs epitaxial quantum rod

Author

Sek, G., Podemski, P., Misiewicz, J., Li, L., Fiore, A., Patriarche, G., Sek, G., Podemski, P., Misiewicz, J., Li, L., Fiore, A., and Patriarche, G.

Abstract

Microphotoluminescence (µ-PL) experiment has been performed on a structure with InGaAs/GaAs epitaxial quantum rods (quantum dots with the aspect ratio as high as 4.1) grown by depositing short-period InAs/GaAs superlattice by molecular beam epitaxy on GaAs substrate. The exciton and biexciton emission from a single quantum rod has been detected via the excitation power dependence of the µ-PL spectra. The origin of the single rod lines has been confirmed by a rate equation model. For a number of quantum rods within the investigated ensemble, the biexciton binding energy has been determined to be in the range of 1.0–2.2 meV.

Published
2008

360. Fabrication and characterization of a room-temperature ZnO polariton laser

Author

Li, Feng, primary, Orosz, L., additional, Kamoun, O., additional, Bouchoule, S., additional, Brimont, C., additional, Disseix, P., additional, Guillet, T., additional, Lafosse, X., additional, Leroux, M., additional, Leymarie, J., additional, Malpuech, G., additional, Mexis, M., additional, Mihailovic, M., additional, Patriarche, G., additional, Réveret, F., additional, Solnyshkov, D., additional, and Zuniga-Perez, J., additional

Published
2013
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361. From Excitonic to Photonic Polariton Condensate in a ZnO-Based Microcavity

Author

Li, Feng, primary, Orosz, L., additional, Kamoun, O., additional, Bouchoule, S., additional, Brimont, C., additional, Disseix, P., additional, Guillet, T., additional, Lafosse, X., additional, Leroux, M., additional, Leymarie, J., additional, Mexis, M., additional, Mihailovic, M., additional, Patriarche, G., additional, Réveret, F., additional, Solnyshkov, D., additional, Zuniga-Perez, J., additional, and Malpuech, G., additional

Published
2013
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362. Semibulk InGaN: A novel approach for thick, single phase, epitaxial InGaN layers grown by MOVPE

Author

Pantzas, K., primary, El Gmili, Y., additional, Dickerson, J., additional, Gautier, S., additional, Largeau, L., additional, Mauguin, O., additional, Patriarche, G., additional, Suresh, S., additional, Moudakir, T., additional, Bishop, C., additional, Ahaitouf, A., additional, Rivera, T., additional, Tanguy, C., additional, Voss, P.L., additional, and Ougazzaden, A., additional

Published
2013
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364. Structural and compositional characterization of MOVPE GaN thin films transferred from sapphire to glass substrates using chemical lift-off and room temperature direct wafer bonding and GaN wafer scale MOVPE growth on ZnO-buffered sapphire

Author

Gautier, S., primary, Moudakir, T., additional, Patriarche, G., additional, Rogers, D.J., additional, Sandana, V.E., additional, Hosseini Téherani, F., additional, Bove, P., additional, El Gmili, Y., additional, Pantzas, K., additional, Sundaram, Suresh, additional, Troadec, D., additional, Voss, P.L., additional, Razeghi, M., additional, and Ougazzaden, A., additional

Published
2013
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368. Polarization dependence study of electroluminescence and absorption from InAsGaAs columnar quantum dots

Author

Ridha, P., Li, L., Fiore, A., Patriarche, G., Mexis, M., Smowton, P.M., Ridha, P., Li, L., Fiore, A., Patriarche, G., Mexis, M., and Smowton, P.M.

Abstract

Semiconductor optical amplifiers based on InGaAs columnar quantum dots (CQDs) with different numbers of superlattice periods were fabricated and tested. The polarization dependence of the electroluminescence (EL) and absorption of such CQDs structures were measured. Compared to standard QDs a large improvement in the ratio of transverse-magnetic (TM) and -electric (TE) integrated EL was obtained in CQDs, depending on the number of stacked GaAsInAs superlattice periods, which can be attributed to the more symmetric shape of CQDs. TM and TE resolved photovoltage absorption spectroscopy confirmed this improvement. A small spectral separation between TE- and TM-EL peaks has been observed showing that heavy and light holelike states are energetically close in these QDs. © 2007 American Institute of Physics

Published
2007

369. Growth and characterization of InAs columnar quantum dots on GaAs substrate

Author

Li, L., Patriarche, G., Rossetti, M., Fiore, A., Li, L., Patriarche, G., Rossetti, M., and Fiore, A.

Abstract

The growth of InAs columnar quantum dots (CQDs) on GaAs substrates by MBE was studied. The CQDs were formed by depositing a 1.8 monolayer (ML) InAs seed dot layer and a short period GaAs/InAs superlattice (SL). The growth of the CQDs is very sensitive to growth interruption (GI) and growth temp. Both longer GI and higher growth temp. impact the size dispersion of the CQDs, which causes the broadening of photoluminescence (PL) spectrum and the presence of the addnl. PL peak tails. By properly choosing the GI and the growth temp., CQDs including GaAs (3 ML)/InAs (0.62 ML) SL with period no. up to 35 without plastic relaxation were grown. The corresponding equiv. thickness of the SL is 41 nm which is two times higher than the theor. crit. thickness of the strained InGaAs layer with the same av. In compn. of 16%. The increase of the crit. thickness is partially assocd. with the formation of the CQDs. Based on a five-stack CQD active region, laser diodes emitting around 1120 nm at room temp. were demonstrated, indicating a high material quality. CQDs with nearly isotropic cross section (20 nm*20 nm dimensions) were formed by depositing a 16-period GaAs (3 ML)/InAs (0.62 ML) SL on an InAs seed dot layer, indicating the feasibility of artificial shape engineering of QDs. Such a structure is expected to be very promising for polarization insensitive device applications, such as semiconductor optical amplifiers. [on SciFinder (R)]

Published
2007

370. Optical and electronic properties of GaAs-based structures with columnar quantum dots

Author

Motyka, M., Sek, G., Ryczko, K., Andrzejewski, J., Misiewicz, J., Li, L., Fiore, A., Patriarche, G., Motyka, M., Sek, G., Ryczko, K., Andrzejewski, J., Misiewicz, J., Li, L., Fiore, A., and Patriarche, G.

Abstract

The electronic properties of a structure with columnar quantum dots obtained by close stacking of InAs submonolayers were studied by contactless electroreflectance (CER) and photoluminescence. These dots have an almost ideally rectangular cross section and uniform compn., which is promising for polarization independent gain. After energy level calcns. in the effective mass approxn. using compn. profiles obtained from cross-sectional TEM the part of the CER spectrum related to the 2-dimensional surrounding layer was explained and single heavy-hole-like and light-hole-like transitions related to the columnar dots identified, due to a single electron state confined in a shallow in-plane potential. [on SciFinder (R)]

Published
2007

371. Wetting layer states of InAs/GaAs self-assembled quantum dot structures. Effect of intermixing and capping layer

Author

Sek, G., Ryczko, K., Motyka, M., Andrzejewski, J., Wysocka, K., Misiewicz, J., Li, L., Fiore, A., Patriarche, G., Sek, G., Ryczko, K., Motyka, M., Andrzejewski, J., Wysocka, K., Misiewicz, J., Li, L., Fiore, A., and Patriarche, G.

Abstract

The authors present a modulated reflectivity study of the wetting layer (WL) states in mol. beam epitaxy grown InAs/GaAs quantum dot (QD) structures designed to emit light in the 1.3-1.5 micro m range. A high sensitivity of the technique has allowed the observation of all optical transitions in the QD system, including low oscillator strength transitions related to QD ground and excited states, and the ones connected with the WL quantum well (QW). The support of WL content profiles, detd. by transmission electron microscopy, has made it possible to analyze in detail the real WL QW confinement potential which was then used for calcg. the optical transition energies. In spite of a very effective WL QW intermixing, mainly due to the Ga-In exchange process (causing the redn. of the max. indium content in the WL layer to about 35% from nominally deposited InAs), the transition energies remain almost unaffected. The latter effect could be explained in effective mass envelope function calcns. taking into account the intermixing of the QW interfaces described within the diffusion model. We have followed the WL-related transitions of 2 closely spaced QD layers grown at different temps., as a function of the In content in the capping layer. Changing the capping layer from pure GaAs to In0.236Ga0.764As has no significant influence on the compn. profile of the WL itself and the WL QW transitions can be usually interpreted properly when based on the cap-induced modification of the confinement potential within a squarelike QW shape approxn. However, some of the obsd. features could be explained only after taking into consideration the effects of intermixing and InGaAs cap layer decompn. [on SciFinder (R)]

Published
2007

373. Nondestructive Characterization of Residual Threading Dislocation Density in HgCdTe Layers Grown on CdZnTe by Liquid-Phase Epitaxy.

Author

Fourreau, Y., Pantzas, K., Patriarche, G., and Destefanis, V.

Subjects
DISLOCATION density, DENSITOMETERS, EPITAXIAL layers, THERMAL oxidation (Materials science), CRYSTAL growth
Abstract

The performance of mercury cadmium telluride (MCT)-based infrared (IR) focal-plane arrays is closely related to the crystalline perfection of the HgCdTe thin film. In this work, Te-rich, (111)B-oriented HgCdTe epilayers grown by liquid-phase epitaxy on CdZnTe substrates have been studied. Surface atomic steps are shown on as-grown MCT materials using atomic force microscopy (AFM) and white-light interferometry (WLI), suggesting step-flow growth. Locally, quasiperfect surface spirals are also evidenced. A demonstration is given that these spirals are related to the emergence of almost pure screw threading dislocations. A nondestructive and quantitative technique to measure the threading dislocation density is proposed. The technique consists of counting the surface spirals on the as-grown MCT surface from images obtained by either AFM or WLI measurements. The benefits and drawbacks of both destructive-chemical etching of HgCdTe dislocations-and nondestructive surface imaging techniques are compared. The nature of defects is also discussed. Finally, state-of-the-art threading dislocation densities in the low 10 cm range are evidenced by both etch pit density (EPD) and surface imaging measurements. [ABSTRACT FROM AUTHOR]

Published
2016
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375. Aberration Corrected STEM to Study an Ancient Hair Dyeing Formula.

Author

Patriarche, G., Van Elslande, E., Castaing, J., and Walter, P.

Subjects
*HAIR dyeing & bleaching, *LEAD, *SALTS, *NANOCRYSTALS, *QUANTUM dots, *LEAD sulfide, *LEAD oxides, *KERATIN
Abstract

Lead-based chemistry was initiated in ancient Egypt for cosmetic preparation more than 4000 years ago. Here, we study a hair-dyeing recipe using lead salts described in text since Greco-Roman times. We report direct evidence about the shape and distribution of PbS nanocrystals that form within the hair during blackening. [ABSTRACT FROM AUTHOR]

Published
2014
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379. FIB carving of nanopores into suspended graphene films

Author

Morin, A., primary, Lucot, D., additional, Ouerghi, A., additional, Patriarche, G., additional, Bourhis, E., additional, Madouri, A., additional, Ulysse, C., additional, Pelta, J., additional, Auvray, L., additional, Jede, R., additional, Bruchhaus, L., additional, and Gierak, J., additional

Published
2012
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388. Distributed Bragg reflectors based on diluted boron-based BAlN alloys for deep ultraviolet optoelectronic applications

Author

Abid, M., primary, Moudakir, T., additional, Orsal, G., additional, Gautier, S., additional, En Naciri, A., additional, Djebbour, Z., additional, Ryou, J.-H., additional, Patriarche, G., additional, Largeau, L., additional, Kim, H. J., additional, Lochner, Z., additional, Pantzas, K., additional, Alamarguy, D., additional, Jomard, F., additional, Dupuis, R. D., additional, Salvestrini, J.-P., additional, Voss, P. L., additional, and Ougazzaden, A., additional

Published
2012
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392. Structural analysis of site-controlled InAs/InP quantum dots

Author

Fain, B., primary, Elvira, D., additional, Le Gratiet, L., additional, Largeau, L., additional, Beaudoin, G., additional, Troadec, D., additional, Abram, I., additional, Beveratos, A., additional, Robert-Philip, I., additional, Patriarche, G., additional, and Sagnes, I., additional

Published
2011
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395. Efficient photogeneration of charge carriers in silicon nanowires with a radial doping gradient

Author

Murthy, D H K, primary, Xu, T, additional, Chen, W H, additional, Houtepen, A J, additional, Savenije, T J, additional, Siebbeles, L D A, additional, Nys, J P, additional, Krzeminski, C, additional, Grandidier, B, additional, Stiévenard, D, additional, Pareige, P, additional, Jomard, F, additional, Patriarche, G, additional, and Lebedev, O I, additional

Published
2011
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396. Gold anchoring on Si sawtooth faceted nanowires

Author

Boukhicha, R., primary, Gardès, C., additional, Vincent, L., additional, Renard, C., additional, Yam, Vy., additional, Fossard, F., additional, Patriarche, G., additional, Jabeen, F., additional, and Bouchier, D., additional

Published
2011
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