Working principles of doping-well structures for high-mobility two-dimensional electron systems

Abstract

Suppressing electron scattering is essential to achieve high-mobility two-dimensional electron systems (2DESs) that are clean enough to probe exotic interaction-driven phenomena. In heterostructures it is common practice to utilize modulation doping, where the ionized dopants are physically separated from the 2DES channel. The doping-well structure augments modulation doping by providing additional screening for all types of charged impurities in the vicinity of the 2DES, which is necessary to achieve record-breaking samples. Despite its prevalence in the design of ultra-high-mobility 2DESs, the working principles of the doping-well structure have not been reported. Here we elaborate on the mechanics of electron transfer from doping wells to the 2DES, focusing on GaAs/AlGaAs samples grown by molecular beam epitaxy. Based on this understanding we demonstrate how structural parameters in the doping well can be varied to tune the properties of the 2DES.

arXiv comment6 pages, 5 fitures

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• Understanding limits to mobility in ultra-high-mobility GaAs two-dimensional electron systems: The quest for 100 million cm${}^2$/Vs and beyond
• Moving crystal phases of a quantum Wigner solid in an ultra-high-quality 2D electron system
• Fractional quantum Hall effect energy gap: role of electron layer thickness
• Scattering mechanisms in state-of-the-art GaAs/AlGaAs quantum wells
• Density-dependent two-dimensional optimal mobility in ultra-high-quality semiconductor quantum wells
• Theory of intrinsic acoustic plasmons in twisted bilayer graphene
• Delocalization and Universality of the Fractional Quantum Hall Plateau-to-Plateau Transitions
• Screening effects of superlattice doping on the mobility of GaAs two-dimensional electron system revealed by in-situ gate control
• Composite Fermion Mass
• Ultraclean two-dimensional hole systems with mobilities exceeding 10${}^7$ cm${}^2$/Vs
• Electron spectra in double quantum wells of different shapes
• Dependences of the Transport Scattering Time and Quantum Lifetime on the Two-Dimensional Electron Gas Density in Modulation-Doped Single GaAs Quantum Wells with AlAs/GaAs Short-Period Superlattice Barriers
• Melting phase diagram of bubble phases in high Landau levels
• Impact of in-situ controlled disorder screening on fractional quantum Hall effects and composite-fermion transport
• Heterostructure design to achieve high quality, high density GaAs 2D electron system with $g$-factor tending to zero