Achievement of Systematically Higher Transport Mobilities for a Large Range of Two-dimensional Electron Densities in GaAs Quantum Wells
ORAL
Abstract
For the range of two-dimensional (2D) electron densities between 1.5 x 1010 cm-2 and 1.4 x 1011 cm-2, we report measurements that confirm a ~60 to 70 % increase in the transport mobility of remotely-doped GaAs quantum wells compared to all previous GaAs material. A characteristic example of this development is the 2D transport mobility at an electron density of 1 x 1011 cm-2 in a 50 nm quantum well. Previously, in this type of sample the electron mobilities were limited to ~ 1.8 x 107 cm2V-1s-1; now we have grown several with transport mobilities reaching ~3.0 x 107 cm2V-1s-1. We attribute these results to our program of high-temperature in-situ bakes that have cleaned our AlGaAs barrier material of oxygen impurities, and to the use of large-area cryogenic cold-plates operating at 17 K in the vacuum sump of our molecular beam epitaxy chamber. When cooled to temperatures below 100 mK, the magnetotransport data of the 1 x 1011 cm-2 samples described above are remarkable, displaying clear quantum Hall features at the Landau level filling factors ν = 11/23, 12/25, and even 13/27.
*Work supported by the NSF (Grants DMR 1709076, ECCS 1906253, and MRSEC DMR 1420541), the DOE Basic Energy Sciences (Grant DE-FG02-00-ER45841), and the Gordon and Betty Moore Foundation (Grant GBMF4420).
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Presenters
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Loren Pfeiffer
- Princeton University
- Electrical Engineering, Princeton University
- Electrical engineering, Princeton university
- Princeton Univ
- Department of Electrical Engineering, Princeton University
- electrical engineering, Princeton
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA