Bismuth-containing semiconductors: Linear and nonlinear optical susceptibilities of GaAs1−xBix alloys

Using all electron full potential – linearized augmented plane wave (FP-LAPW) method the linear and nonlinear optical susceptibilities of cubic GaAs1−xBix alloys with x varying between 0.25 and 0.75 with increment of 0.25 are investigated. We have applied the generalized gradient approximation (GGA) for the exchange and correlation potential. In addition the Engel–Vosko generalized gradient approximation (EVGGA) was used. The reflectivity, refractivity, absorption coefficient and the loss function of these ternary alloys were investigated. The absorption coefficient shows that GaAs0.25Bi0.75 possess the highest coefficient among the investigated alloys which supports our previous observation that the band gap decreases substantially with increasing Bi content and the materials with very small energy band gap possess the highest absorption coefficient. The investigation of the linear and nonlinear optical susceptibilities of GaAs1−xBix shows a strong band gap reduction as commonly found experimentally.

► Linear and nonlinear optical susceptibilities of GaAs1−xBix alloys were investigated. ► The reflectivity, refractivity, absorption coefficient and the loss function were analyzed. ► The absorption coefficient shows that GaAs0.25Bi0.75 possesses the highest coefficient among the investigated alloys. ► We observed that the band gap decreases substantially with increasing Bi content. ► GaAs1−xBix alloys with very small energy band gap possess the highest absorption coefficient.