We present the structural properties of ternary InxGa₁-xN (0.20 x 0.80) alloys grown on sapphire substrate by plasma-assisted molecular beam epitaxy. High resolution X-ray diffraction (HR-XRD) analyses were used to investigate the phase and crystalline quality of ternary InxGa1-xN. From the XRD phase analysis, it is confirmed that the films InxGa₁-xN had wurtzite structure and without any phase separation. In addition, it is found that the Bragg angle of the (0002) InxGa₁-xN peak gradually decreases as the In compositions increases, indicating the increases in the lattice constant c of the InxGa₁-xN ternary alloys. Apart from that, the composition of InxGa₁-xN epilayers is determined by applying the Vegard’s law. Finally, the variation of the crystalline quality as a function of In composition is investigated through the XRD rocking curve analyses.
