First-principles investigation of lattice constants and bowing parameters in wurtzite AlxGa1-xN, InxGa1-xN and InxAl1-xN alloys

First-principles calculations, by means of the full-potential augmented plane wave method using the local density approximation, were carried out for the structural and electronic properties of the AlxGa1-xN, InxGa1-xN and InxAl1-xN alloys in the wurtzite structure. We have investigated the lattice parameters and band gap energies. The lattice constants a and c are found to change linearly for the AlxGa1-xN alloy, while for both InxGa1-xN and InxAl1-xN alloys the lattice parameters, a, exhibit an upward bowing. The calculated band gap variation for the three alloys exhibit a downward bowing of 0.71 eV, 1.7 eV and 4.09 eV for AlxGa1-xN, InxGa1-xN and InxAl1-xN, respectively.