Energy gaps and refractive indices of AlxGa1-xAs

The composition dependence of energy gaps and refractive indices in the Alx Ga1-xAs alloy system in the zincblende structure are reported within the ps eudopotential framework under the virtual crystal approximation in which th e effect of composition disorder is involved. The calculated energy gaps and refractive indices are in good agreement wit h experiments for the parent compounds, whereas for the AlxGa1-xAs it appea rs necessary to include the disorder effect. The variation of the refractiv e index as a function of the photon energy for different concentrations x s hows that this later behaves differently for different Al mole fractions x and that the disorder effect on the refractive index depends strongly on th e alloy composition x. (C) 2001 Elsevier Science B.V. All rights reserved.