Abstract: The electric field domains and self-sustained oscillations formed under applied DC bias in doped weakly-coupled GaAs/AlAs superlattices were investigated. The transitions between stable and dynamic domains and the mechanisms responsible for the generation of self-sustained oscillations by light illumination, temperature variation and transverse magnetic field were analyzed. The behavior of the vertical transport of electrons was proved to be critically influenced by the line shape of the electric field dependence of the effective drift velocity, V(B,F). The room temperature GHz range frequency microwave oscillations were realized in the narrow-barrier GaAs/AlAs superlattice diodes.