SPACE-CHARGE BUILDUP IN TIGHT-BINDING SUPERLATTICES INDUCED BY ELECTRON SEQUENTIAL TUNNELING

High-field domain formation in semiconductor structures with tight-bin ding GaAs/AlGaAs superlattices has been studied using capacitance-volt age (C-V) measurements. Accumulation of the electrons in the quantum w ells during the extension of the high-field domain through the superla ttice as a result of increasing bias is detected as a sharp increase i n the capacitance. The comparison between the C-V and current-voltage (I-V) characteristics is discussed in terms of the extension of the hi gh-field domain through the entire superlattice. Measurements performe d at 77 K show clear oscillations in the I-V and the C-V characteristi cs, from which the space charge accumulation in the superlattice can b e calculated. (C) 1995 Academic Press Limited