CARRIER TRANSPORT IN INAS/ALSB/GASB INTERBAND TUNNELING STRUCTURES

A three-band model that considers the coupling effects among the conduction band, light-hole band, and spin-orbit split-off-hole band is used to investigate carrier transport in InAs/AlSb/GaSb interband tunneling structures. The E-k relations and the boundary conditions suitable for the three-band model are derived from the Hamiltonian. Good agreement in the peak current density and peak voltage between experiments and model has been achieved. It is also found that the three-band model shows better agreement in the peak current densities than those of two-band model. It indicates the importance of the coupling effects of the spin-orbit split-off-hole band to the InAs/AlSb/GaSb interband tunneling structures. The valley current components, the key ingredient of the peak-to-valley current ratios, such as the thermionic currents and hole tunneling current, are studied to fit the experimental peak-to-valley current ratios. It is found that the thermionic currents can be neglected due to the large band offset (barrier height). The hole tunneling current, the major part of valley current, decreases with the AlSb barrier thickness. However, deviations from the experiments still exist. Furthermore, the effect of the band bending at the interfaces influences the I-V characteristics.