First principles investigation of optical properties of zinc-blende AlxGa1−xAs1−yNy materials

We have performed a first-principle Full Potential Linearized Augmented Plane Waves calculation within the local density approximation (LDA) to the zinc-blende AlxGa1−xAs1−yNy to predict its optical properties as a function of N and Al mole fractions. The accurate calculations of electronic properties such as band structures and optical properties like refractive index, reflectivity and absorption coefficient of AlxGa1−xAs and AlxGa1−xAs1−yNy with x≤0.375 and y up to 4% are presented. AlxGa1−xAs on GaAs have a lattice mismatch less than 0.16% and the lattice constant of AlxGa1−xAs has a derivation parameter of 0.0113±0.0024. The band gap energies are calculated by LDA and the band anticrossing model using a matrix element of CMN=2.32 and a N level of EN=(1.625+0.069x) eV. The results show that AlxGa1−xAs can be very useful as a barrier layer in separate confinement heterostructure lasers and indicate that the best choice of x and y AlxGa1−xAs1−yNy could be an alternative to AlxGa1−xAs when utilized as active layers in quantum well lasers and high-efficiency solar cell structures.