Calculations of plasma wavelength in highly doped III-V semiconductor alloys

A detailed study of the dependence of the plasma wavelength on the doping concentration in ternary and quaternary III-V semiconductor alloys has been made. The band-structure properties are included in the calculations by applying the triple-band effective-mass equations to an extended Drude formula. The results show that for high doping levels the plasma wavelengths of the considered materials (InAsxSb1−x, GaxIn1−xSb, GaAs1−xSbx, In1−xGaxAs, In1−xGaxAsyP1−y, and AlxGayIn1−x−yAs) saturate into the 10-μm-wavelength region (the smaller the band gap, the larger the saturation wavelength). The optimal material group for the realization of the plasma resonance for 10.6 μm (CO2 lasers) seems to be In0.53Ga0.47As. Numerical fits for the plasma wavelength and the optical effective mass are provided.