First-Principles Calculation of Structural and Electronic Properties of Wurtzite Al_xGa_1—xN, In_xGa_1—xN, and In_xAl_1—xN Random Alloys

Abstract

Using first-principles method, we studied the influence of alloying on the structural and electronic properties of the Al_xGa_1—xN, In_xGa_1—xN, and In_xAl_1—xN random alloys in the wurtzite structure. For Al_xGa_1—xN, the lattice constants a and c are found to follow the Vegard law, while for both In_xGa_1—xN and In_xAl_1—xN the lattice parameters, a, exhibit an upward bowing of —0.09 and —0.16 Å, respectively. The calculated band structures for the three alloys show a direct-gap, and exhibit a downward bowing of 0.71, 1.7, and 4.09 eV for Al_xGa_1—xN, In_xGa_1—xN, and In_xAl_1—xN, respectively.