Electronic Properties of Semimetallic Heterojunctions

Abstract

The properties of InAs–GaSb heterojunctions containing a semimetallic electron–hole double layer at the heterointerface have been considered. By self-consistent calculations of interface accumulation and inversion layers, band diagrams, capacitance–voltage and current–voltage characteristics were analyzed for all possible combinations of the semiconductor doping types, namely, for n–p, n–n, p–p and p–n-heterojunctions. The n-InAs–p-GaSb junction containing accumulation layers in both semiconductors, has the most unusual properties including the capacitance growth with the increase of contact potential and metallic conductivity caused by activationless generation–recombination processes at the interface. A phenomenological theory of these processes is developed, which can also describe the conductivity of long-period InAs–GaSb superlattices. One more remarkable effect is the strong frequency dispersion of capacitance in p-InAs–n-GaSb junctions caused by the re-charging of a single or double inversion layer at the interface.