Structural and optical properties of Al1-xInxN epilayers on GaN template grown by metalorganic chemical vapor deposition

This paper reports that Al_1-xIn_xN epilayerswere grown on GaN template by metalorganic chemical vapor depositionwith an In content of 7%--20%. X-ray diffraction results indicatethat all these Al_1-xIn_xN epilayers have a relatively lowdensity of threading dislocations. Rutherfordbackscattering/channeling measurements provide the exactcompositional information and show that a gradual variation incomposition of the Al_1-xIn_xN epilayer happens along thegrowth direction. The experimental results of optical reflectionclearly show the bandgap energies of Al_1-xIn_xNepilayers. A bowing parameter of 6.5~eV is obtained from thecompositional dependence of the energy gap. The cathodoluminescencepeak energy of the Al_1-xIn_xN epilayer is much lower than itsbandgap, indicating a relatively large Stokes shift in the Al_1-xIn_xN sample.