Direct Eoenergy gaps of bismuth-containing III—V alloys predicted using quantum dielectric theory

Quantum dielectric theory has been used to predict the direct Eo energy gaps of ternary and quaternary III-V semiconductor alloys containing up to ~10 mol % InBi. The calculated composition dependence of Eo for InSb_{1 - x} Bix is in good agreement with experimental results with a predicted semiconductor-semimetal transition (77 K) at x = 0.124. E₀ (77 K) values corresponding to infrared wavelengths of 8 to 12 pm are obtained at x = 0.043-0.070, respectively, corresponding to lattice mismatches with InSh substrates in the range from 0.11 % to 0.17%. The quaternary alloys InAs_{1 … x … y} Sb_x Biy and In_{1 - x} Ga_x Sb_{1 - y} Bi_y also yield Eu values in this range with similar Inm contents while maintaining exact lattice match to InSb substrates. InAs_{1 - x} Bi_x is proposed as a new alloy for spanning the wavelength range from 3 to 5 pm. The required x values range from 0 to 0.079 (measuring Eo at 77 K) and the maximum lattice mismatch with either InAs or GaSb substrates for these compositions is < 0.31 %. The related quaternary alloy In_{1 … x} Ga_x As_{1 … y} Biy also spans the 3-5 pm wavelength range while maintaining lattice match with InAs or GaSb substrates.