Influence of surface states on quantum and transport lifetimes in high-quality undoped heterostructures.

We present a comparison between experimental and theoretical values of transport τt and quantum τq scattering lifetimes in high-quality undoped Al0.34Ga0.66As/GaAs heterostructures. We obtain excellent agreement between the experimental and modeled scattering times using three scattering processes: background impurity, interface roughness, and remote ionized impurity scattering from surface states. We show that despite the high mobility μpeak = 5.6 × 106 cm² V-1 s-1), the quantum lifetime τq is significantly reduced by small-angle scattering from remote surface charge. We further show that in shallow devices scattering from surface charges will be a limiting factor for both transport and quantum lifetimes. [ABSTRACT FROM AUTHOR]