Band diagram of the InAs$_{1-y}$Sb$_{y}$/InAsSbP heterojunction in the composition range $y<$ 0.2

The $n^{+}$-InAs/$n^{0}$-InAs$_{1-y}$Sb$_{y}$/$p$-InAsSbP heterostructures with asymmetric band offsets at the heterointerfaces of the active region were grown by organometallic vapor phase epitaxy on the InAs substrates. Sections with tunneling conductance were observed in the forward branch of the current-voltage characteristics of the obtained heterostructures at low temperatures. The energy band diagram of the InAs/InAs$_{1-y}$Sb$_y$/InAsSbP double heterostructure was calculated in the composition range ($y<$ 0.2) of a narrow-gap active region. It was shown that the InAs$_{1-y}$Sb$_{y}$/InAsSbP heterojunction is a type II heterojunction in the given composition range. The experimentally observed electroluminescence for the $n^{+}$-InAs/$n^{0}$-InAs$_{1-y}$Sb$_{y}$/$p$-InAsSbP heterostructures with an active region in the composition range $y>$ 0.14 was due to interfacial radiative transitions involving localized hole states at the type II heterointerface.