Wide AlAs quantum wells with > 106 cm2V-1s-1 mobility

ORAL

Abstract

Modulation-doped Al0.33Ga0.67As/AlAs/Al0.33Ga0.67As quantum wells with electron densities of 1.4, 2.2, and 3.3 x 1011 cm-2 were grown with well widths ranging from 11 nm to 50 nm. In these samples electrons occupy in-plane valleys with large and anisotropic effective masses (longitudinal and transverse effective masses are 1.0 and 0.21, in units of free electron mass). We find that the optimized well width varies according to sample density, most likely because of scattering contributions from the second sub-band. Our highest quality samples show exceptional mobility values as high as 2.4 x 106 cm2V-1s-1 at the density of 2.2 x 1011 cm-2, and we observe high order fractional quantum Hall states up to 8/15 in samples with 1.4 x 1011 cm-2 density. These advances clearly demonstrate that 2D electrons in AlAs now have quality comparable to modern GaAs, highlighting the system as an excellent candidate to study electron-electron interactions in an anisotropic, multi-valley environment.

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Presenters

  • Edwin Chung

    Princeton Univ, EE, Princeton University

Authors

  • Edwin Chung

    Princeton Univ, EE, Princeton University

  • K Baldwin

    Princeton University, Princeton Univ, Electrical Engineering, Princeton Univ, Department of Electrical Engineering, Princeton University, EE, Princeton University

  • K West

    Electrical Engineering, princeton university, Department of Electrical Engineering, Princeton University, Princeton University, Univ of Basel, Princeton Univ, Electrical Engineering, Princeton Univ, EE, Princeton University

  • Mansour Shayegan

    Princeton Univ, Electrical Engineering, Princeton Univ, Department of Electrical Engineering, Princeton University, EE, Princeton University

  • Loren Pfeiffer

    Electrical Engineering, princeton university, Department of Electrical Engineering, Princeton University, Princeton University, Princeton Univ, Electrical Engineering, Princeton Univ, EE, Princeton University