Electronic properties of InAlAs and InGaAs alloys containing a few percent of Bi

Adding a few percent of Bi to III-V conventional semiconductors such as GaAs, InAs, and AlAs, leads to drastic changes in their electronic properties. The band gaps decrease and the spin-orbit splitting increases by sizeable amounts, with a small lattice mismatch to the parent compound, enabling interesting heterostructure materials for optoelectronic applications. In this work, we present a theoretical study of the electronic and optical properties of Bi-alloyed InAlAs and InGaAs ternary alloys using hybrid functional HSE06 calculations. We investigate the effects of adding a few atomic percent of Bi to these alloys, analyzing the changes in the band gap, spin-orbit coupling, and band alignments. We find that Bi doping reduces the band gap and enhances the spin-orbit coupling in both InAlAs and InGaAs alloys, resulting in tunable band gaps and band alignments that are of interest to heterostructure devices. Our results provide useful insights for the design and optimization of dilute InAlAsBi and InGaAsBi quaternary alloys that are promising for infrared device applications.