Effects of Bi on band gap bowing in InP 1- xBix alloys

The effects of Bi in InP1-xBix ternary semiconductor alloys are studied based on first-principles. The mBJLDA potential is used to obtain accurate band structures. The band gap is modified mainly by the large Bi atom-induced strain at high concentration. The incorporation of Bi mainly perturbs the valence bands due to the interaction of Bi impurity states with heavy/light hole bands and spin-orbit split off bands. Several different Bi complexes including [100] chain, [111] chain, clustered and SQS in a 128-atom supercell are considered. For random Bi distribution at high concentration, the resulting band structures can be understood together as a work of all Bi complexes arrangements. Measuring band gap narrowing mechanism dependent on configurations as a function of Bi composition can potentially help to distinguish the types of Bi arrangement distributions in samples as well as to promote the applications in mid-infrared regime.