We report on a flexible eight-band model, derived from a modified Kane
base, generating a transfer-matrix formalism to calculate the transmi
ssion probability of carriers through, and the in-plane dispersion rel
ations of, stratified media. We apply this model to study InAs/AlSb/Ga
Sb/AlSb/InAs interband resonant-tunneling diodes. We show that the bou
ndary-condition sets deduced from current continuity and the boundary-
condition sets deduced from a Hermitian Hamiltonian defined across the
interface are equal. A simplified triple-band model is found to be a
good approximation to calculate the deep light-hole energy levels in a
resonant interband tunneling diode. However, these simplified triple-
band approximations are no longer valid when the carriers have an in-p
lane momentum.