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Ivan Favero - One of the best experts on this subject based on the ideXlab platform.
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microscopic nanomechanical dissipation in Gallium Arsenide resonators
Physical Review Letters, 2018Co-Authors: M Hamoumi, Laurence Morgenroth, A Lemaitre, Giuseppe Leo, Pierre Etienne Allain, W Hease, Eduardo Gilsantos, Bruno Gerard, Ivan FaveroAbstract:We report on a systematic study of nanomechanical dissipation in high-frequency (≈300 MHz) Gallium Arsenide optomechanical disk resonators, in conditions where clamping and fluidic losses are negligible. Phonon-phonon interactions are shown to contribute with a loss background fading away at cryogenic temperatures (3 K). Atomic layer deposition of alumina at the surface modifies the quality factor of resonators, pointing towards the importance of surface dissipation. The temperature evolution is accurately fitted by two-level systems models, showing that nanomechanical dissipation in Gallium Arsenide resonators directly connects to their microscopic properties. Two-level systems, notably at surfaces, appear to rule the damping and fluctuations of such high-quality crystalline nanomechanical devices, at all temperatures from 3 to 300 K.
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Microscopic Nanomechanical Dissipation in Gallium Arsenide Resonators
Physical review letters, 2018Co-Authors: M Hamoumi, Laurence Morgenroth, Giuseppe Leo, Pierre Etienne Allain, W Hease, Bruno Gerard, Eduardo Gil-santos, Aristide Lemaître, Ivan FaveroAbstract:We report on a systematic study of nanomechanical dissipation in high-frequency ($\ensuremath{\approx}300\text{ }\text{ }\mathrm{MHz}$) Gallium Arsenide optomechanical disk resonators, in conditions where clamping and fluidic losses are negligible. Phonon-phonon interactions are shown to contribute with a loss background fading away at cryogenic temperatures (3 K). Atomic layer deposition of alumina at the surface modifies the quality factor of resonators, pointing towards the importance of surface dissipation. The temperature evolution is accurately fitted by two-level systems models, showing that nanomechanical dissipation in Gallium Arsenide resonators directly connects to their microscopic properties. Two-level systems, notably at surfaces, appear to rule the damping and fluctuations of such high-quality crystalline nanomechanical devices, at all temperatures from 3 to 300 K.
Seth M Hubbard - One of the best experts on this subject based on the ideXlab platform.
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Gallium Arsenide solar cells grown on polycrystalline germanium substrates by aluminum induced crystallization
Photovoltaic Specialists Conference, 2019Co-Authors: Elisabeth L Mcclure, Julia R Drozario, Stephen J Polly, Seth M HubbardAbstract:In this study, Gallium Arsenide solar cells were grown on three substrates: a polycrystalline germanium substrate created by aluminum-induced crystallization, a polycrystalline germanium substrate with an average grain size of 400 µm from Umicore, and a monocrystalline (100) germanium substrate with a 6° offcut from Umicore. The solar cells created by aluminuminduced crystallization showed a V OC up to 0.17 V, which was comparable to the solar cells grown on the Umicore polycrystalline germanium substrates that exhibited a range of V OC from 0.20 V to 0.40 V. Device performance further improved when concentrating the solar cells, where a V OC of 0.4 V, J SC of 7.9 mA/cm2, and an efficiency of 0.023% was achieved under 67 suns for the solar cells grown on a germanium substrate prepared by aluminum-induced crystallization.
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investigation of deep level defects in electron irradiated indium Arsenide quantum dots embedded in a Gallium Arsenide matrix
Materials Science in Semiconductor Processing, 2014Co-Authors: W Strong, David V Forbes, Seth M HubbardAbstract:Abstract Gallium Arsenide diodes with and without indium Arsenide quantum dots were electron irradiated to investigate radiation induced defects. Baseline and quantum dot Gallium Arsenide pn-junction diodes were characterized by capacitance–voltage measurements, and deep level transient spectroscopy. Carrier accumulation was observed in the Gallium Arsenide quantum dot sample at the designed depth for the quantum dots via capacitance–voltage measurements. Prior to irradiation, a defect 0.84 eV below the conduction band (EC – 0.84 eV) was observed in the baseline sample which is consistent with the native EL2 defect seen in Gallium Arsenide. After 1 MeV electron irradiation three new defects were observed in the baseline sample, labeled as E3 (EC – 0.25 eV), E4 (EC – 0.55 eV), and E5 (EC – 0.76 eV), consistent with literature reports of electron irradiated Gallium Arsenide. Prior to irradiation, the addition of quantum dots appeared to have introduced defect levels at EC – 0.21, EC – 0.38, and EC – 0.75 eV denoted as QD–DX1, QD–DX2, and QD–EL2 respectively. In the quantum dot sample after 1 MeV electron irradiation, QD–E3 (EC – 0.28 eV), QD–E4 (EC – 0.49 eV), and QD–EL2 (EC – 0.72 eV) defects, similar to the baseline sample, were observed, although the trap density was dissimilar to that of the baseline sample. The quantum dot sample showed a higher density of the QD–E4 defect and a lower density of QD–E3, while the QD–EL2 defect seemed to be unaffected by electron irradiation. These findings suggest that the quantum dot sample may be more radiation tolerant to the E3 defect as compared to the baseline sample.
Laurence Morgenroth - One of the best experts on this subject based on the ideXlab platform.
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microscopic nanomechanical dissipation in Gallium Arsenide resonators
Physical Review Letters, 2018Co-Authors: M Hamoumi, Laurence Morgenroth, A Lemaitre, Giuseppe Leo, Pierre Etienne Allain, W Hease, Eduardo Gilsantos, Bruno Gerard, Ivan FaveroAbstract:We report on a systematic study of nanomechanical dissipation in high-frequency (≈300 MHz) Gallium Arsenide optomechanical disk resonators, in conditions where clamping and fluidic losses are negligible. Phonon-phonon interactions are shown to contribute with a loss background fading away at cryogenic temperatures (3 K). Atomic layer deposition of alumina at the surface modifies the quality factor of resonators, pointing towards the importance of surface dissipation. The temperature evolution is accurately fitted by two-level systems models, showing that nanomechanical dissipation in Gallium Arsenide resonators directly connects to their microscopic properties. Two-level systems, notably at surfaces, appear to rule the damping and fluctuations of such high-quality crystalline nanomechanical devices, at all temperatures from 3 to 300 K.
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Microscopic Nanomechanical Dissipation in Gallium Arsenide Resonators
Physical review letters, 2018Co-Authors: M Hamoumi, Laurence Morgenroth, Giuseppe Leo, Pierre Etienne Allain, W Hease, Bruno Gerard, Eduardo Gil-santos, Aristide Lemaître, Ivan FaveroAbstract:We report on a systematic study of nanomechanical dissipation in high-frequency ($\ensuremath{\approx}300\text{ }\text{ }\mathrm{MHz}$) Gallium Arsenide optomechanical disk resonators, in conditions where clamping and fluidic losses are negligible. Phonon-phonon interactions are shown to contribute with a loss background fading away at cryogenic temperatures (3 K). Atomic layer deposition of alumina at the surface modifies the quality factor of resonators, pointing towards the importance of surface dissipation. The temperature evolution is accurately fitted by two-level systems models, showing that nanomechanical dissipation in Gallium Arsenide resonators directly connects to their microscopic properties. Two-level systems, notably at surfaces, appear to rule the damping and fluctuations of such high-quality crystalline nanomechanical devices, at all temperatures from 3 to 300 K.
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surface enhanced Gallium Arsenide photonic resonator with quality factor of 6 10 6
Optica, 2017Co-Authors: Biswarup Guha, Felix Marsault, F Cadiz, Laurence Morgenroth, Vladimir Ulin, Vladimir Berkovitz, A Lemaitre, Carmen Gomez, A Amo, Sylvain CombrieAbstract:Gallium Arsenide and related compound semiconductors lie at the heart of optoelectronics and integrated laser technologies. Shaped at the micro- and nanoscale, they allow strong interaction with quantum dots and quantum wells, and promise stunning optically active devices. However, Gallium Arsenide optical structures presently exhibit lower performance than their passive counterparts based on silicon, notably in nanophotonics, where the surface plays a chief role. Here, we report on advanced surface control of miniature Gallium Arsenide optical resonators using two distinct techniques that produce permanent results. One extends the lifetime of free carriers and enhances luminescence, while the other strongly reduces surface absorption and enables ultra-low optical dissipation devices. With such surface control, the quality factor of wavelength-sized optical disk resonators is observed to rise up to 6×106 at the telecom wavelength, greatly surpassing previous realizations and opening new prospects for Gallium Arsenide nanophotonics.
Giuseppe Leo - One of the best experts on this subject based on the ideXlab platform.
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microscopic nanomechanical dissipation in Gallium Arsenide resonators
Physical Review Letters, 2018Co-Authors: M Hamoumi, Laurence Morgenroth, A Lemaitre, Giuseppe Leo, Pierre Etienne Allain, W Hease, Eduardo Gilsantos, Bruno Gerard, Ivan FaveroAbstract:We report on a systematic study of nanomechanical dissipation in high-frequency (≈300 MHz) Gallium Arsenide optomechanical disk resonators, in conditions where clamping and fluidic losses are negligible. Phonon-phonon interactions are shown to contribute with a loss background fading away at cryogenic temperatures (3 K). Atomic layer deposition of alumina at the surface modifies the quality factor of resonators, pointing towards the importance of surface dissipation. The temperature evolution is accurately fitted by two-level systems models, showing that nanomechanical dissipation in Gallium Arsenide resonators directly connects to their microscopic properties. Two-level systems, notably at surfaces, appear to rule the damping and fluctuations of such high-quality crystalline nanomechanical devices, at all temperatures from 3 to 300 K.
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Microscopic Nanomechanical Dissipation in Gallium Arsenide Resonators
Physical review letters, 2018Co-Authors: M Hamoumi, Laurence Morgenroth, Giuseppe Leo, Pierre Etienne Allain, W Hease, Bruno Gerard, Eduardo Gil-santos, Aristide Lemaître, Ivan FaveroAbstract:We report on a systematic study of nanomechanical dissipation in high-frequency ($\ensuremath{\approx}300\text{ }\text{ }\mathrm{MHz}$) Gallium Arsenide optomechanical disk resonators, in conditions where clamping and fluidic losses are negligible. Phonon-phonon interactions are shown to contribute with a loss background fading away at cryogenic temperatures (3 K). Atomic layer deposition of alumina at the surface modifies the quality factor of resonators, pointing towards the importance of surface dissipation. The temperature evolution is accurately fitted by two-level systems models, showing that nanomechanical dissipation in Gallium Arsenide resonators directly connects to their microscopic properties. Two-level systems, notably at surfaces, appear to rule the damping and fluctuations of such high-quality crystalline nanomechanical devices, at all temperatures from 3 to 300 K.
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parametric fluorescence in oxidized aluminum Gallium Arsenide waveguides
Applied Physics Letters, 2001Co-Authors: A De Rossi, V Berger, M Calligaro, Giuseppe Leo, V Ortiz, X MarcadetAbstract:Parametric fluorescence in low-loss oxidized aluminum Gallium Arsenide heterostructure waveguides is quantitatively analyzed. A parametric fluorescence efficiency as high as 6×10−7 W/W has been measured in a 3.2-mm-long waveguide. This corresponds to a normalized conversion efficiency, scaled with the waveguide length, of about 1000% cm−2 W−1, eight times higher than with LiNbO3 waveguides. This opens the perspective of a microoptical parametric oscillation threshold below 100 mW.
Aaron J Ptak - One of the best experts on this subject based on the ideXlab platform.
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Gallium Arsenide solar cells grown at rates exceeding 300 µm h 1 by hydride vapor phase epitaxy
Nature Communications, 2019Co-Authors: Wondwosen Metaferia, Kevin L Schulte, John Simon, Steve Johnston, Aaron J PtakAbstract:We report Gallium Arsenide (GaAs) growth rates exceeding 300 µm h−1 using dynamic hydride vapor phase epitaxy. We achieved these rates by maximizing the Gallium to Gallium monochloride conversion efficiency, and by utilizing a mass-transport-limited growth regime with fast kinetics. We also demonstrate Gallium indium phosphide growth at rates exceeding 200 µm h−1 using similar growth conditions. We grew GaAs solar cell devices by incorporating the high growth rate of GaAs and evaluated its material quality at these high rates. Solar cell growth rates ranged from 35 to 309 µm h−1 with open circuit voltages ranging from 1.04 to 1.07 V. The best devices exceeded 25% efficiency under the AM1.5 G solar spectrum. The high open-circuit voltages indicate that high material quality can be maintained at these extremely high growth rates. These results have strong implications toward lowering the deposition cost of III-V materials potentially enabling the deposition of high efficiency devices in mere seconds. Gallium Arsenide holds record efficiency for single junction solar cells, but high production costs limit applications. Here Metaferia et al. show high quality GaAs and GaInP at rates exceeding 300 and 200 micrometers per hour by dynamic hydride vapor phase epitaxy and > 25% efficient solar cells.
