Electrical Isolation of Type Ⅱ InAs/InGaSb Superlattices from GaSb Substrates

摘要

We show here that n-type InAs/InGaSb superlattices can be electrically isolated from lightly doped n-type GaSb substrates at much higher temperatures than from the more common undoped p-type GaSb substrates without the use of a large band gap insulating buffer layer. Temperature dependent Hall effect measurements show superlattice conduction up to near room temperature, which is significantly higher than the 20 K observed for p-type substrates. Multi-carrier analysis of magnetic field dependent transport data demonstrate the absence of a substrate related conduction channel. We argue that the isolation is due to the depletion layer at the p-n junction between the p-type buffer layer and the n-type substrate.