Multilayer structures based on variable-gap semiconductors: carrier redistribution phenomena during current transfer

Abstract

The paper theoretically investigates the peculiarities of carrier redistribution taking place in periodic semiconductor variable-gap multilayer structures during current transfer in the direction perpendicular to the layers. It is studied in detail the cases of homogeneously doped symmetric and asymmetric structures with linear coordinate dependence of energy gap. Current transport in variable multilayer structures is shown to accompany with the substantial spatial redistribution of minority carriers resulting in deviation of carrier concentration from its equilibrium value. At strong fields the practically constant carrier concentration is set up in almost the whole volume of structure for the exception of thin regions in the vicinity of the interfaces. In the case of asymmetric structures carrier redistribution can give rise to changing the total number of carriers what is displayed on current- voltage characteristics.