COMPOSITION AND TEMPERATURE-DEPENDENCE OF THE REFRACTIVE-INDEX IN CD1-XMGXTE EPITAXIAL-FILMS

We report on optical reflection measurements on ternary alloy (CdMg)Te thin films grown by molecular beam epitaxy. Data have been obtained in the spectral range between 1.2 eV and 2.8 eV, and at temperatures between 300 K and 77 K. The reflection coefficient as a function of energy E has been theoretically described taking into account multiple reflections at the interfaces involved. The dispersion relation n2(E) = a + bE2/[1 - (E/c)2] has been used. A comparison with the experimental data has yielded the refractive index as a function of energy. The value of the refractive index n is given as a function of energy lor the ternary alloy (CdMg)Te for different Mg concentrations and different temperatures. These results are essential for designing efficient waveguides for semiconductor laser structures using (CdMg)Te as a base material.