First-Principles Study of Structural and Electronic Properties of GaNxAs1-X Alloys

Using first-principles total energy calculations, we have studied the structural and electronic properties of GaN _x As _1-x alloys within density-functional theory (DFT) framework. The validity of Local density approximation (LDA) and generalized gradient approximation (GGA) has been demonstrated by the calculations of lattice parameters and band-gap bowing. The results show that LDA is relatively more suitable for calculations of GaNAs alloy. The lattice constant calculated decreases in line with vegard's law in contrast to that the band gap has big composition-dependent bowing parameters. The effects of relaxed atoms and bonds have also been discussed. The relaxation contributes significantly to band-gap bowing.