Optical properties of InGaAs/InAlAs metamorphic nanoheterostructures for photovoltaic converters of laser and solar radiation

Reflectance spectroscopy has been used to determine the refractive indices of nanoscale In$_{x}$Al$_{y}$Ga$_{1-x-y}$As and In$_{x}$Al$_{1-x}$As layers with indium and aluminum concentrations $x$ = 0.21–0.24 and $y$ = 0, 0.1, and 0.2 on specially created Bragg-reflector heterostructures at wavelengths in the range 700–2000 nm. It was demonstrated that the method based on an analysis of the auto- and cross-correlation coefficients of the wavelength derivatives of the dependence of the reflectance of structures of this kind in order to determine the dispersion curves of the materials forming a reflector. It was found that raising the concentration of indium in InGaAs and AlInAs leads to a substantial rise in the refractive index, with a preserved spectral run of the refractive indices, which is characteristic of gallium arsenide and aluminum arsenide.