Modeling the optical constants of GaP, InP, and InAs

The optical constants of GaP, InP and InAs in the spectral range from 1 to 6 eV were modeled. An extension of the Adachi model with the adjustable broadening function was employed. Adjustable broadening was modeled by supplanting the damping constant with the frequency-dependent expression. The enhanced flexibility of the model allowed excellent agreement with experimental data. The relative rms errors for the refractive index were 1.2% for GaP, 1.0% for InP and 1.6% for InAs.