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R S Goldman - One of the best experts on this subject based on the ideXlab platform.

  • influence of gaas Surface Termination on gasb gaas quantum dot structure and band offsets
    Applied Physics Letters, 2013
    Co-Authors: Eric S Zech, A S Chang, Andrew J Martin, Justin C Canniff, Joanna Mirecki Millunchick, R S Goldman
    Abstract:

    We have investigated the influence of GaAs Surface Termination on the nanoscale structure and band offsets of GaSb/GaAs quantum dots (QDs) grown by molecular-beam epitaxy. Transmission electron microscopy reveals both coherent and semi-coherent clusters, as well as misfit dislocations, independent of Surface Termination. Cross-sectional scanning tunneling microscopy and spectroscopy reveal clustered GaSb QDs with type I band offsets at the GaSb/GaAs interfaces. We discuss the relative influences of strain and QD clustering on the band offsets at GaSb/GaAs interfaces.

  • Influence of GaAs Surface Termination on GaSb/GaAs quantum dot structure and band offsets
    Applied Physics Letters, 2013
    Co-Authors: Eric S Zech, A S Chang, Andrew J Martin, Justin C Canniff, Joanna Mirecki Millunchick, R S Goldman
    Abstract:

    We have investigated the influence of GaAs Surface Termination on the nanoscale structure and band offsets of GaSb/GaAs quantum dots (QDs) grown by molecular-beam epitaxy. Transmission electron microscopy reveals both coherent and semi-coherent clusters, as well as misfit dislocations, independent of Surface Termination. Cross-sectional scanning tunneling microscopy and spectroscopy reveal clustered GaSb QDs with type I band offsets at the GaSb/GaAs interfaces. We discuss the relative influences of strain and QD clustering on the band offsets at GaSb/GaAs interfaces.

Zhicheng Zhong - One of the best experts on this subject based on the ideXlab platform.

  • atomic scale metal insulator transition in srruo3 ultrathin films triggered by Surface Termination conversion
    Advanced Materials, 2020
    Co-Authors: Lingfei Wang, Liang Si, Xiaoyue He, Daniel G Porter, Eun Kyo Ko, Sung Min Park, Alessandro Bombardi, Zhicheng Zhong
    Abstract:

    The metal-insulator transition (MIT) in transition-metal-oxide is fertile ground for exploring intriguing physics and potential device applications. Here, an atomic-scale MIT triggered by Surface Termination conversion in SrRuO3 ultrathin films is reported. Uniform and effective Termination engineering at the SrRuO3 (001) Surface can be realized via a self-limiting water-leaching process. As the Surface Termination converts from SrO to RuO2 , a highly insulating and nonferromagnetic phase emerges within the topmost SrRuO3 monolayer. Such a spatially confined MIT is corroborated by systematic characterizations on electrical transport, magnetism, and scanning tunneling spectroscopy. Density functional theory calculations and X-ray linear dichroism further suggest that the Surface Termination conversion breaks the local octahedral symmetry of the crystal field. The resultant modulation in 4d orbital occupancy stabilizes a nonferromagnetic insulating Surface state. This work introduces a new paradigm to stimulate and tune exotic functionalities of oxide heterostructures with atomic precision.

Jory A. Yarmoff - One of the best experts on this subject based on the ideXlab platform.

  • Surface Termination of cleaved bi2se3 investigated by low energy ion scattering
    Physical Review Letters, 2013
    Co-Authors: Xiaofeng He, Wenjun Zhou, Zhiyong Wang, Yanning Zhang, Ruqian Wu, Jory A. Yarmoff
    Abstract:

    It has been widely assumed that Se terminates the Surface of the topological insulator, bismuth selenide. Although some Se is initially at the Surface after cleaving at 80 K, low energy ion scattering reveals a complete Bi Termination at room temperature. Density functional theory shows that a Bi bilayer atop the bulk-terminated structure is energetically favorable. It is thus proposed that a thermally activated process induces a spontaneous Termination change after cleaving. This has profound implications on the electrical transport and long-term stability of such materials and devices.

  • Surface Termination of cleaved Bi2Se3investigated by low energy ion scattering
    Physical Review Letters, 2013
    Co-Authors: Xiaofeng He, R. Q. Wu, Wenjun Zhou, J. Shi, Y N Zhang, Z. Y. Wang, Jory A. Yarmoff
    Abstract:

    It has been widely assumed that Se terminates the Surface of the topological insulator, bismuth selenide. Although some Se is initially at the Surface after cleaving at 80 K, low energy ion scattering reveals a complete Bi Termination at room temperature. Density functional theory shows that a Bi bilayer atop the bulk-terminated structure is energetically favorable. It is thus proposed that a thermally activated process induces a spontaneous Termination change after cleaving. This has profound implications on the electrical transport and long-term stability of such materials and devices.

Mitsuhiro Katayama - One of the best experts on this subject based on the ideXlab platform.

  • unpredicted Surface Termination of α fe2o3 0001 film grown by mist chemical vapor deposition
    Surface Science, 2017
    Co-Authors: Shun Osaka, Osamu Kubo, Kazuki Takahashi, Kentaro Kaneko, Hiroshi Tabata, Shizuo Fujita, Mitsuhiro Katayama
    Abstract:

    Abstract We analyze the Surface structure of an α-Fe 2 O 3 (0001) film grown on a c-plane sapphire substrate by mist chemical vapor deposition (CVD), which has been recently developed as a simple, safe, and cost-effective film growth method. Using coaxial impact-collision ion scattering spectroscopy, we found that the atomic-layer sequence of the Surface Termination of an α-Fe 2 O 3 (0001) film grown by mist CVD was Fe–O 3 –Fe– from the top layer. This Surface Termination is predicted to form in an oxygen-poor environment by density functional theory combined with a thermodynamical approach despite that the mist CVD process is performed with atmospheric-pressure air. The Surface structure markedly changes after annealing above 600 °C in ultrahigh vacuum. We found that only a couple of layers from the top layer transform into Fe 3 O 4 (111) after 650 °C annealing, which would be so-called biphase reconstruction. Complete transformation into a Fe 3 O 4 (111) film occurs at 700 °C, whose atomic-layer sequence is determined to be Fe–O 4 –Fe 3 – from the top layer.

  • Surface Termination structure of α ga2o3 film grown by mist chemical vapor deposition
    Applied Physics Letters, 2016
    Co-Authors: Daiki Tamba, Shun Osaka, Osamu Kubo, Kazuki Takahashi, Kentaro Kaneko, Hiroshi Tabata, Shizuo Fujita, Mitsuhiro Katayama
    Abstract:

    The Surface structure of α-Ga2O3(0001) grown on an α-Al2O3(0001) substrate by mist chemical vapor deposition was studied by coaxial impact-collision ion scattering spectroscopy (CAICISS) and atomic force microscopy (AFM). The minimum step height observed in the AFM image was 0.21 ± 0.01 nm, coinciding with the height of three atomic layers of α-Ga2O3(0001). It was revealed by CAICISS analysis that the Surface of α-Ga2O3(0001) is terminated by a Ga layer followed by an O layer, which is consistent with the Surface Termination of α-Al2O3(0001). A structural model taking Surface relaxation into account was also constructed by fitting the simulated curve for the azimuth angle dependence of the Ga intensity to the experimental dependence. The resultant structural model is similar to the model of an α-Al2O3(0001) Surface, which indicates analogous behavior in corundum crystals.

Eric S Zech - One of the best experts on this subject based on the ideXlab platform.

  • influence of gaas Surface Termination on gasb gaas quantum dot structure and band offsets
    Applied Physics Letters, 2013
    Co-Authors: Eric S Zech, A S Chang, Andrew J Martin, Justin C Canniff, Joanna Mirecki Millunchick, R S Goldman
    Abstract:

    We have investigated the influence of GaAs Surface Termination on the nanoscale structure and band offsets of GaSb/GaAs quantum dots (QDs) grown by molecular-beam epitaxy. Transmission electron microscopy reveals both coherent and semi-coherent clusters, as well as misfit dislocations, independent of Surface Termination. Cross-sectional scanning tunneling microscopy and spectroscopy reveal clustered GaSb QDs with type I band offsets at the GaSb/GaAs interfaces. We discuss the relative influences of strain and QD clustering on the band offsets at GaSb/GaAs interfaces.

  • Influence of GaAs Surface Termination on GaSb/GaAs quantum dot structure and band offsets
    Applied Physics Letters, 2013
    Co-Authors: Eric S Zech, A S Chang, Andrew J Martin, Justin C Canniff, Joanna Mirecki Millunchick, R S Goldman
    Abstract:

    We have investigated the influence of GaAs Surface Termination on the nanoscale structure and band offsets of GaSb/GaAs quantum dots (QDs) grown by molecular-beam epitaxy. Transmission electron microscopy reveals both coherent and semi-coherent clusters, as well as misfit dislocations, independent of Surface Termination. Cross-sectional scanning tunneling microscopy and spectroscopy reveal clustered GaSb QDs with type I band offsets at the GaSb/GaAs interfaces. We discuss the relative influences of strain and QD clustering on the band offsets at GaSb/GaAs interfaces.