Space charge buildup in tight-binding superlattices induced by electron sequential tunneling

High-field domain formation in semiconductor structures with tight-binding GaAs/AlGaAs superlattices has been studied using capacitance-voltage (C-V) measurements. Accumulation of the electrons in the quantum wells during the extension of the high-field domain through the superlattice as a result of increasing bias is detected as a sharp increase in the capacitance. The comparison between the C-V and current-voltage (I-V) characteristics is discussed in terms of the extension of the high-field domain through the entire superlattice. Measurements performed at 77 K show clear oscillations in the I-V and the C-V characteristics, from which the space charge accumulation in the superlattice can be calculated. (C) 1995 Academic Press Limited