Fig. 1. Schematic diagram of superlattice of semiconductor materials. (a) Periodic change of impurity in single crystal semiconductor; (b) periodic change of alloy composition^[20]

Fig. 2. Bandgap structure of type-Ⅱ InAs/GaSb strained layer superlattice^[22]

Fig. 3. Schematic diagram of the band alignment between InAs and InAsSb. (a) InAs_1-xsb_x superlattice structure with low Sb component and ordered arrangement; (b) InAs/InAs_0.93Sb_0.07 structure grown on InAs substrate; (c) mass reduction results for two transitions

Fig. 4. Schematic diagram of device structure. (a) NBN structure detector; (b) energy band diagram ideal NBN structure under reverse bias

Fig. 5. Schematic diagram of the device structure. (a) P⁺-N-N⁺ structure detector; (b) PBN structure detector; (c) double barrier PBN structure detector

Fig. 6. Schematic diagram of band structure of device. (a) PBP structure; (b) CBIRD structure