Refractive indices of InAlAs and InGaAs/InP from 250 to 1900 nm determined by spectroscopic ellipsometry

2 μm thick layers of MBE-grown In0.53Ga0.47As and In0.52Al0.48As on InP are measured with spectroscopic ellipsometry in the wavelength range from 245 to 845 nm and the fitted n,k dispersion curves given. From 450 to 845 nm the real and imaginary part of the refractive index of In0.52Al0.48As are about 0.1 higher than those of InP. The angle of incidence of two ellipsometers are controlled by measuring the same sample at different wavelengths and a correction for one ellipsometer is made. About 0.5 μm thick In0.53Ga0.47As and In0.52Al0.48As layers on InP are measured in the same manner and in addition from 410 to 1900 nm to determine the n,k values for this wavelength range. For the fitting procedure an interface layer between the substrate and the ternary layer is necessary. First results are given.