Scattering Mechanism in Modulation-Doped Shallow Two-Dimensional Electron Gases

Abstract

We report on a systematic investigation of the dominant scattering mechanism in shallow two-dimensional electron gases (2DEGs) formed in modulation-doped GaAs/Al_{x}Ga_{1-x}As heterostructures. The power-law exponent of the electron mobility versus density, mu \propto n^{alpha}, is extracted as a function of the 2DEG's depth. When shallower than 130 nm from the surface, the power-law exponent of the 2DEG, as well as the mobility, drops from alpha \simeq 1.65 (130 nm deep) to alpha \simeq 1.3 (60 nm deep). Our results for shallow 2DEGs are consistent with theoretical expectations for scattering by remote dopants, in contrast to the mobility-limiting background charged impurities of deeper heterostructures.

4 pages, 3 figures, modified version as accepted in APL

References in corpus (2)

• Limit to 2D mobility in modulation-doped GaAs quantum structures: How to achieve a mobility of 100 millions
• Transport and percolation in a low-density high-mobility two-dimensional hole system

Cited by in corpus (5)

• InAs-Al Hybrid Devices Passing the Topological Gap Protocol
• The Impact of Small-Angle Scattering on Ballistic Transport in Quantum Dots
• Distinguishing impurity concentrations in GaAs and AlGaAs, using very shallow undoped heterostructures
• Ultra-shallow quantum dots in an undoped GaAs/AlGaAs 2D electron gas
• Field-effect-induced two-dimensional electron gas utilizing modulation doping for improved ohmic contacts