Transition from the type-II broken-gap heterojunction to the staggered one in the GaInAsSb/InAs(GaSb) system

Abstract

Conditions for the transition from the staggered heterojunction to the type-II broken-gap one were considered for isolated Ga_1−x In_xAs_ySb_1−y /InAs(GaSb) heterostructures in relation to the quaternary alloy composition. Energy-band diagrams of such heterojunctions were estimated and energy band offsets Δ at the heterointerface were determined. It was experimentally found that the type-II broken-gap heterojunction in the Ga_1−x In_xAs_ySb_1−y /p-InAs structure is observed in the entire range of composition parameters under study, 0.03 < x < 0.23, and becomes staggered in the range 0.3 < x < 1. In p-Ga_1−x In_xAs_ySb_1−y /p-GaSb heterostructures with the indium content 0.85 < x < 0.92 in the solid phase, the p-type conductivity is observed, which is indicative of the staggered heterojunction. At x > 0.92, the contribution of electrons of the semimetal channel at the heterointerface to the total conductivity was observed, as well as the transition from the staggered heterojunction to the type-II broken-gap one.