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.

6 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