Аннотация:A theoretical study is made of the characteristics of heterostructures made of compounds InAs, GaSb, and AlSb or their solid solutions. The many-band approximation and the effective mass method are used to derive expressions for the transmission coefficients of quasiparticles (electrons or light holes) tunneling in such structures. The case of normal incidence of an electron or a light hole on a heterojunction is considered (heavy holes do not then participate in the tunneling process). It is shown that the conversion of quasiparticles at heterojunctions plays a significant role in the operation of devices made of the investigated materials.