Optimisation of experimental conditions for variable angle spectroscopic ellipsometry analysis. Application to GaAs/(Al,Ga)As quantum well characterisation

For variable angle spectroscopic ellipsometry (VASE), a systematic research of the best set of angles of incidence taking into account sensitivities of the spectra to the thickness and dielectric function as well as correlation can significantly improve the accuracy of studies. A procedure minimising the expected uncertainties of the parameters is developed. A GaAs/(Al,Ga)As quantum well structure has been investigated using the above experimental procedure. Deduced composition and thickness from VASE and photoluminescence experiments are in good agreement with reflectivity results.