Growth and electrical transport properties of very high mobility two-dimensional hole gases displaying persistent photoconductivity

Henini, M.; Rodgers, P.J.; Crump, P.; Gallagher, B. L.; Hill, G.

doi:10.1063/1.112791

Cited by 39 publications

(30 citation statements)

References 16 publications

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“…5,15 This progress has stimulated the investigation of Wigner crystallization 16 and the fractional quantum Hall effect 17 in heterojunctions containing 2DHS. The subband dispersion in zero magnetic field ͑normal to the plane͒ has been probed in a qualitative fashion using magnetotunneling spectroscopy and found to be satisfactorily modeled by existing calculations, even for the high-index oriented samples.…”

Section: ϫ2mentioning

confidence: 99%

Cyclotron resonance in ultra-low-hole-density narrow p-type GaAs/(Al,Ga)As quantum wells

et al. 1997

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The cyclotron-resonance behavior of a series of p-type, low p s , asymmetrically doped ͑311͒A quantum wells has been measured over two orders of magnitude in energy. Landau levels for the structures studied have been calculated for comparison with experiment. The calculations use a rotated Luttinger Hamiltonian and invoke the axial approximation. In the quantum limit and at certain far-infrared energies we observe two resonances widely separated in field. We find at the lowest fields that the samples exhibit a light effective mass. For the narrowest quantum well the cyclotron resonance ͑CR͒ broadens and shifts to a slightly lighter mass into the quantum limit, above about 2 T. The CR energy is modeled by inter-Landau-level transitions from the highest level, and a discontinuous evolution to a higher effective mass, observed as the second resonance above 8 T, is explained by crossing of the highest two Landau levels, as modeled in the calculation. The discontinuous evolution to a higher mass is found to shift to lower fields as the well width increases, as suggested from the modeling. For the wider quantum wells the influence of additional anticrossings at intermediate fields, due to the proximity of the second subband, is observed. CR energy for these samples is adequately modeled at energies above and below the region of subband anticrossing. The limitations of the modeling procedure have been discussed and a number of features of the experimental data are explained qualitatively in terms of the expected modifications to the hole Landau-level structure when full Landau-level mixing is incorporated into the modeling. The influence of hole-hole interactions and factors influencing the CR scattering time are also discussed briefly. ͓S0163-1829͑97͒08804-8͔

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Section: ϫ2mentioning

confidence: 99%

Cyclotron resonance in ultra-low-hole-density narrow p-type GaAs/(Al,Ga)As quantum wells

et al. 1997

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“…To mention a few examples, the use of non-͑001͒ substrates has allowed the fabrication of ultrahigh mobility two-dimensional hole gases in GaAs/ AlGaAs heterostructures, high-performance InAs/ GaAs quantum dot ͑QD͒ lasers, InGaAs/ GaAs QDs with enhanced piezoelectric effects, and GaMnAs epilayers with modified Mn incorporation and magnetic anisotropies. [7][8][9] In this study, we explore the growth by molecular beam epitaxy ͑MBE͒ of GaBiAs alloys on ͑311͒B GaAs substrates. We use a series of structural and optical techniques to characterize the as-grown material and to determine the amount of Bi incorporated into the samples.…”

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confidence: 99%

Molecular beam epitaxy of GaBiAs on (311)B GaAs substrates

Henini

Ibáñez

Schmidbauer

et al. 2007

Applied Physics Letters

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We report the growth by molecular beam epitaxy of GaBi x As 1−x epilayers on ͑311͒B GaAs substrates. We use high-resolution x-ray diffraction ͑HRXRD͒, transmission electron microscopy, and Z-contrast imaging to characterize the structural properties of the as-grown material. We find that the incorporation of Bi into the GaBiAs alloy, as determined by HRXRD, is sizably larger in the ͑311͒B epilayers than in ͑001͒ epilayers, giving rise to reduced band-gap energies as obtained by optical transmission spectroscopy. © 2007 American Institute of Physics. ͓DOI: 10.1063/1.2827181͔ GaBi x As 1−x alloys are attracting in recent years a considerable deal of attention. [1][2][3][4][5][6] The band gap of GaAs is strongly reduced upon the addition of small amounts of Bi ͑ϳ90 meV per percent of Bi͒, with a strong enhancement of the spinorbit splitting energy.3,4 These remarkable properties make the Ga͑In͒BiAs system an attractive candidate to develop GaAs-based applications for long-wavelength optoelectronics as well as for spintronics. While the use of dilute nitrides in device applications is currently limited because the electron mobility of these compounds is abruptly reduced due to strong N-related alloy scattering, dilute bismides might exhibit improved transport properties. 6 The growth of epitaxial layers on high-index planes represents a step forward in semiconductor material engineering, as it offers an additional degree of freedom to develop applications with improved properties with respect to the conventional ͑001͒-grown devices. The interest in non-͑001͒ semiconductor structures is manifold and concerns growth, impurity incorporation, electronic properties, lasing performance, and piezoelectric effects. To mention a few examples, the use of non-͑001͒ substrates has allowed the fabrication of ultrahigh mobility two-dimensional hole gases in GaAs/ AlGaAs heterostructures, high-performance InAs/ GaAs quantum dot ͑QD͒ lasers, InGaAs/ GaAs QDs with enhanced piezoelectric effects, and GaMnAs epilayers with modified Mn incorporation and magnetic anisotropies. [7][8][9] In this study, we explore the growth by molecular beam epitaxy ͑MBE͒ of GaBiAs alloys on ͑311͒B GaAs substrates. We use a series of structural and optical techniques to characterize the as-grown material and to determine the amount of Bi incorporated into the samples. Our results reveal that the incorporation of Bi is enhanced in the ͑311͒B samples in comparison to the conventional ͑001͒ orientation.For this study, GaBi x As 1−x films were grown by MBE on semi-insulating ͑001͒ and ͑311͒B GaAs substrates at a growth temperature ͑T G ͒ of ϳ350°C with different As to Ga flux ratios. The growth was performed in a specially designed MBE reactor ͑see Ref. 10 for details͒. Atomic Ga and Bi were used as group-III and group-V sources, respectively, while As in the form of dimers ͑As 2 ͒ was produced by using a two-zone purpose made cell. In order to incorporate Bi efficiently into MBE-grown GaAs, the Ga to As flux needs to be on the brink of As shortage, close to...

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“…The range of densities for the BL WC in zero magnetic field should be within reach in coupled layers of holes grown along high index crystallographic directions [23], where both high effective masses, to quench the kinetic energy, and high mobilities, to prevent defect-induced localization, can be obtained. …”

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confidence: 99%

Wigner crystallization in quantum electron bilayers

Goldoni¹,

Peeters²

1997

Europhys. Lett.

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The phase diagram of quantum electron bilayers in zero magnetic field is obtained using density functional theory. For large electron densities the system is in the liquid phase, while for smaller densities the liquid may freeze (Wigner crystallization) into four different crystalline phases; the lattice symmetry and the critical density depend on the the inter-layer distance. The phase boundaries between different Wigner crystals consist of both first and second order transitions, depending on the phases involved, and join the freezing curve at three different triple points. 73.20.Dx, 64.70.Dv, 64.70.Kb Typeset using REVT E X 1

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Growth and electrical transport properties of very high mobility two-dimensional hole gases displaying persistent photoconductivity

Cited by 39 publications

References 16 publications

Cyclotron resonance in ultra-low-hole-density narrow p-type GaAs/(Al,Ga)As quantum wells

Cyclotron resonance in ultra-low-hole-density narrow p-type GaAs/(Al,Ga)As quantum wells

Molecular beam epitaxy of GaBiAs on (311)B GaAs substrates

Wigner crystallization in quantum electron bilayers

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