Distinguishing impurity concentrations in GaAs and AlGaAs, using very shallow undoped heterostructures

Abstract

We demonstrate a method of making a very shallow, gateable, undoped 2-dimensional electron gas. We have developed a method of making very low resistivity contacts to these structures and systematically studied the evolution of the mobility as a function of the depth of the 2DEG (from 300nm to 30nm). We demonstrate a way of extracting quantitative information about the background impurity concentration in GaAs and AlGaAs, the interface roughness and the charge in the surface states from the data. This information is very useful from the perspective of molecular beam epitaxy (MBE) growth. It is difficult to fabricate such shallow high-mobility 2DEGs using modulation doping due to the need to have a large enough spacer layer to reduce scattering and switching noise from remote ionsied dopants.

4 pages, 5 eps figures

References in corpus (5)

• The role of background impurities in the single particle relaxation lifetime of a two-dimensional electron gas
• Fabrication and characterization of an induced GaAs single hole transistor
• AlGaAs/GaAs single electron transistors fabricated without modulation doping
• Scattering Mechanism in Modulation-Doped Shallow Two-Dimensional Electron Gases
• Acoustoelectric luminescence from a field-effect n-i-p lateral junction

Cited by in corpus (10)

• Fabrication and characterisation of ambipolar devices on an undoped AlGaAs/GaAs heterostructure
• The Impact of Small-Angle Scattering on Ballistic Transport in Quantum Dots
• Ultra-shallow quantum dots in an undoped GaAs/AlGaAs 2D electron gas
• Fabrication and characterization of an undoped GaAs/AlGaAs quantum dot device
• The origin of gate hysteresis in p-type Si-doped AlGaAs/GaAs heterostructures
• Non-adiabatic single-electron pump in a dopant-free GaAs/AlGaAs 2DEG
• Field-effect-induced two-dimensional electron gas utilizing modulation doping for improved ohmic contacts
• Linear non-hysteretic gating of a very high density 2DEG in an undoped metal-semiconductor-metal sandwich structure
• Mapping an electron wave function by a local electron scattering probe
• Stable electroluminescence in ambipolar dopant-free lateral p-n junctions