AlN content influence on the properties of AlxGa1-xN doped with Pr ions

The purpose of this work is the study of the structural and optical properties of AlxGa1-xN films grown on (0 0 0 1) sapphire substrates with different AlN molar fraction implanted with 150 key of praseodymium ions with a fluence of 2.5 x 1014 cm(-2). The main goal is to achieve the optical doping of AlxGa1-xN with the rare earth Pr. Structural properties, damage accumulation and Pr lattice site location were studied combining Rutherford backscattering/channeling spectrometry and high resolution X-ray diffraction. The channeling data clearly indicate a higher resistance of the lattice to irradiation damage with the increase of the AlN content. Detailed angular scans reveal a fraction above 90% of Pr incorporated in near substitutional sites. A pronounced narrowing at the bottom of the Pr angular curve along the c-axis suggests the presence of a minor fraction with a higher displacement towards the center of the channel. The displacement is less pronounced with the increase of Ga content in the samples. Ionoluminescence with a H-1(+) microbeam reveal an enhancement of the optical activity when the AlN content is in the intermediate range of concentrations. (C) 2011 Elsevier B.V. All rights reserved.