Electronic Structure of GaxIn1-xSbyAs1-y: Band Alignments Based on UTB Calculations

The valence band maximum and the conduction band miminum of GaAs, GaSb, InAs, and InSb (constituent binaries of the quaternaty alloy ) are calculated by using TB analytical approach method. The band alignment types of their heterojunctions are determined directly from their relative position of band edges (VBM and CBM). For example, the GaAs/InAs, GaAs/InSb, and GaSb/InSb are in a type-I, the GaAs/GaSb in a type-II, and the GaSb/InAs and InSb/InAs in a type-III, respectively. The composition dependent VBM and CBM for the alloy are obtained by using the univeral tight binding method. For the alloyed heterojunctions, the band alignments can be controlled by changing the composition which induce a band type transition. For the alloy lattice mathced to GaSb, the type-II band alignment in the region of is changed to the type-III in the region of . On the other hand, the alloy lattice mathced to InAs has the type-II band alignment in the region of and the type-III band alignment in the region of , respectively.