Interface roughness scattering and electron mobilities in thin gaas quantum wells

The mobility of the two-dimensional electron gas in thin GaAs multiple quantum well structures is studied. At low temperatures a strong decrease is found for well widths between 60 Å and 40 Å. This can be explained by interface roughness scattering. The measured electron density dependence of the mobility is used to determine the roughness parameters Λ ≈ 65 Å an Δ ≈ 2.4 Å. The importance of the penetration of the electron wave function into the barrier is discussed.