The Experts below are selected from a list of 1041 Experts worldwide ranked by ideXlab platform

Michael J. Manfra - One of the best experts on this subject based on the ideXlab platform.

  • molecular beam epitaxy of ultra high quality algaas gaas heterostructures enabling physics in low dimensional electronic systems
    Annual Review of Condensed Matter Physics, 2014
    Co-Authors: Michael J. Manfra
    Abstract:

    Among very-low-disorder systems of condensed matter, the high-mobility two-dimensional electron gas (2DEG) confined in Aluminum Gallium Arsenide (AlGaAs)–Gallium Arsenide (GaAs) heterostructures holds a privileged position as a platform for the discovery of new electronic states driven by strong Coulomb interactions. Molecular beam epitaxy (MBE), an ultra-high vacuum (UHV), thin-film deposition technique, produces the highest quality 2DEGs and has played a central role in a number of discoveries that have at their root the interplay of reduced dimensionality, strong electron-electron interactions, and disorder. This review attempts to describe the latest developments in heterostructure design, MBE technology, and the evolution of our understanding of disorder that result in improved material quality and facilitate discovery of new phenomena at ever finer energy scales.

  • molecular beam epitaxy of ultra high quality algaas gaas heterostructures enabling physics in low dimensional electronic systems
    arXiv: Mesoscale and Nanoscale Physics, 2013
    Co-Authors: Michael J. Manfra
    Abstract:

    Among very low disorder systems of condensed matter, the high mobility two-dimensional electron gas confined in Gallium Arsenide/Aluminum Gallium Arsenide heterostructures holds a privileged position as platform for the discovery of new electronic states driven by strong Coulomb interactions. Molecular beam epitaxy (MBE), an ultra-high vacuum thin-film deposition technique, produces the highest quality 2DEGs and has played a central role in a number of discoveries that have at their root the interplay of reduced dimensionality, strong electron-electron interactions, and disorder. This review attempts to describe the latest developments in heterostructure design, MBE technology, and our evolving understanding of disorder that result in improved material quality and facilitate discovery of new phenomena at ever finer energy scales.

W D Hunt - One of the best experts on this subject based on the ideXlab platform.

  • comment on surface acoustic wave properties of Aluminum Gallium Arsenide j appl phys 66 90 1989
    Journal of Applied Physics, 1991
    Co-Authors: F M Fliegel, Victor E Steele, W D Hunt
    Abstract:

    The conclusions reached in the previous work [Steel et al., J. Appl. Phys. 66, 90 (1989)] are essentially correct, but are in error in that exponents of four and two should not have been used in Eqs. (31) and (32), respectively. The effect on power reduction requirements to achieve a given surface acoustic wave electrical potential are thus proportional to the coupling coefficient (k2 ) ratio for the two materials being compared, rather than the square of the coupling coefficient ratio. Additionally, factors reflecting other differences in properties for different substrate materials or materials systems are included in the modified result. Finally, it is observed that the expressions derived do not necessarily allow the performance of acoustic charge transport (ACT) devices to be determined, but do allow such estimates to be made for heterostructure ACT (HACT) devices.

Giuseppe Leo - One of the best experts on this subject based on the ideXlab platform.

  • frequency doubling and parametric fluorescence in a four port Aluminum Gallium Arsenide photonic chip
    Optics Letters, 2020
    Co-Authors: Iannis Roland, Ivan Favero, Adrien Borne, M Ravaro, R De Oliveira, Stephan Suffit, Pascal Filloux, A Lemaitre, Giuseppe Leo
    Abstract:

    In this Letter, we report on the fabrication and characterization of a monolithic III–V semiconductor photonic chip, designed to perform nonlinear parametric optical processes for frequency conversion and non-classical state generation. This chip co-integrates an AlGaAs microdisk that is evanescently coupled to two distinct suspended waveguides designed for light injection and collection around 1600 nm and 800 nm, respectively. Quasi-phase matching provided by the resonator geometry and material symmetry, resonant field enhancement, and confinement ensure efficient nonlinear interactions. We demonstrate second-harmonic generation efficiency of 5%W−1 and a biphoton generation rate of 1.2 kHz/µW through spontaneous down-conversion.

  • parametric fluorescence in oxidized Aluminum Gallium Arsenide waveguides
    Applied Physics Letters, 2001
    Co-Authors: A De Rossi, V Berger, M Calligaro, Giuseppe Leo, V Ortiz, X Marcadet
    Abstract:

    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.

Heinrich Nickel - One of the best experts on this subject based on the ideXlab platform.

  • in situ investigation of Aluminum Gallium Arsenide Gallium Arsenide multilayer structures under inert and reactive media by atomic force microscopy
    Analytical Chemistry, 1995
    Co-Authors: Thomas Prohaska, Gernot Friedbacher, M Grasserbauer, Heinrich Nickel, Rainer Loesch, W Schlapp
    Abstract:

    In this paper we describe the analytical benefits of in situ preparation and imaging under inert and reactive media using an AlGaAs/GaAs superlattice structure as a well-defined model sample. Imaging under inert organic liquids like toluene has been made possible by means of a home-built sample holder which has been designed for mechanical mounting of small-scale, cleaved specimens and witch works without polymer seals in the liquid cell. The results show that sensitive surfaces can be protected from atmospheric influences without the need for ultrahigh-vacuum conditions. Contrast development on the AlGaAs/GaAs system by preferential oxidation on the AlGaAs layers could be completely suppressed by covering the cross-sectional cleavage surface with toluene. In situ studies of corrosion processes on oxidized AlGaAs/GaAs cleavage surfaces have shown that 0.01 and 0.001 M HCl lead to pitting, while 0.1 M HCl results in a clear contrast inversion of the original corrugation of 0.3-0.6 nm. The described in situ imaging capability significantly enhances the information content of atomic force microscopy (AFM) images, since it allows assignment of chemical information to topographical features primarily seen in AFM images

  • investigation of Aluminum Gallium Arsenide Gallium Arsenide superlattices by atomic force microscopy
    Analytical Chemistry, 1992
    Co-Authors: Gernot Friedbacher, Paul K Hansma, Daniel Schwarzbach, M Grasserbauer, Heinrich Nickel
    Abstract:

    We have analyzed AlGaAs/GaAs superlattices by imaging freshly cleaved, untreated sample cross sections with the atomic force microscope in air. We were also able to image the same superlattice on a sample cross section after etching it for 5 min in 0.1 M HCl. The reverse contrast of the AlGaAs/GaAs multilayer system between both samples suggests an explanation for the observed corrugation of 0.5 nm on the untreated sample and 0.2-0.6 nm on the etched sample

X Marcadet - One of the best experts on this subject based on the ideXlab platform.

  • parametric fluorescence in oxidized Aluminum Gallium Arsenide waveguides
    Applied Physics Letters, 2001
    Co-Authors: A De Rossi, V Berger, M Calligaro, Giuseppe Leo, V Ortiz, X Marcadet
    Abstract:

    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.