Peculiarities of Determination of the Optical Parameters (n and κ) of a Semiconductor Heterostructure from Transmission and Reflection Spectra

In the wavelength range λ = 900–1200 nm, the spectral dependences of the refractive index n and extinction coefficient κ of a thin film, which is the heterostructure based on In0.2Ga0.8As/GaAs quantum wells, are found. The values of n and κ found at each point of the spectrum provide the minimum of the objective function, which is the sum of the module of the differences between the calculated reflection and transmission coefficients and the measured reflection and transmission coefficients of the sample grown on the GaAs substrate.