Scattering processes of 2D electrons by charged quantum dots in n-AlGaAs/GaAs heterojunction channels with 10nm-scale embedded InGaAs islands

摘要

Scattering processes of two-dimensional electrons have been investigated in n-AlGaAs/GaAs heterojunctions where self-organized InGaAs quantum dots are embedded near the channel. The transport lifetimes τ_t, and quantum lifetimes τ_q of electrons have been evaluated as functions of the electron concentrations Ne by measuring and analyzing electron mobilities and Shubnikov de Haas oscillations at 2K. It is found that the ratio τ_t/τ_q is close to 1, indicating that electrons are predominantly scattered by the short range potential intrinsic to the dots. It is also found that the repulsive Coulomb potential induced by trapped electrons in each dot is partly compensated by the attractive potential inherent to each dot.