Ab initio study of electronic properties of BxIn1−xP alloys

Using first-principles calculations in the generalized gradient approximation (GGA), electronic properties of zinc-blende BP and B_xIn_1-xP were studied by CASTEP simulation program. The conduction-band sequence for BP at G point in Brillouin zone(BZ) is p-like Γ_15c and s-like Γ_1c in magnitude sequence, the conduction band minimum (CBM) is along the Δ line between the Γ and X points-at approximately 0.8(1,0,0)2 π/a. Using 32-atom special quasirandom structure (SQS16) to model a random alloy, in the boron concentration of 0-18.75% range for B_xIn_1-xP alloys, a large (6.5eV) and relatively composition-independent direct-gap bowing parameter is obtained, small addition of boron to InP will raise the direct-gap, the average increment in this range is about 12meV/%B.