index of refraction and thickness of materials

ralden

Hi, my current research is to determine the thickness and the index of refraction of semiconductor materials.. using reflectivity.. my adviser gave me the results of the sample by GRAPHS the reflectance percentage vs. the wavelength.. i know that i can measure the index of refraction.. if i know the the thickness.. but in my case i will measure the thickness and the index of refraction simultaneously, i run this at two different angles 90 and 45, so anyone who knows to determine the thickness and index of refraction Using the graph of reflectivity? ty