The effect of the InAs layer thickness on the peak current density and subband properties of the GaSb/InAs/GaSb/AlSb/InAs structures

The incorporation of the InAs layer as the blocking layer into the GaSb side of the GaSb/AlSb/InAs single-barrier interband tunneling structure resulting in a GaSb/InAs/GaSb/AlSb/InAs resonant interband tunneling structure has been proven to greatly enhance negative differential resistance peak-to-valley current ratios and peak current density. The role of the InAs layer induced electron and light hole coupling related to the device performance is then investigated. A three-band model, incorporating the coupling effect of the spin-orbit split-off hole band, is employed to probe the effect of the InAs layer thickness on the peak current densities and the subband properties of the GaSb/InAs/GaSb/AlSb/InAs resonant interband tunneling structures. The calculated peak current densities are in reasonable agreement with the experimental data reported previously. The transmission coefficients based on the three-band calculation can be used to interpret the variations of the peak current densities well. In addition, the ‘‘repulsion’’ of the conduction subbands in the InAs well and light-hole subbands in the GaSb well is observed for larger InAs layer thickness. A ‘‘transition energy region’’ resulting from the crossing of the respective subbands in the InAs and GaSb wells is also observed. The effect of the InAs layer induced subband properties related to the carrier transport in the peak current of the GaSb/InAs/GaSb/AlSb/InAs structure is also discussed.