Optical properties of Pr implanted GaN epilayers and AlxGa1−xN alloys

It has been shown recently that III–V nitrides serve as a good host for rare earth elements and have many potential applications in optical communications. Most work in rare earth implanted III-nitride materials so far has been focused on GaN, while AlGaN alloys should have advantages over GaN due to wider energy band gap. In this work, photoluminescence (PL) spectroscopy was used to investigate praseodymium (Pr) related transitions in Pr-implanted GaN and AlxGa1−xN (0.15<x<0.33). The GaN epilayers and AlxGa1−xN alloys were rapid thermally annealed in nitrogen ambient to facilitate recovery from implantation related damage. We observed narrow PL emission bands near 526, 650, 950, 1100 and 1300 nm. The dependence of PL emission including line width, peak position and emission intensity on sample temperature, excitation intensity, aluminum concentration and annealing conditions were systematically studied. We found that PL intensity increases with annealing time and temperature. In contrast to GaN epilayers, different behaviors have been observed in the AlGaN host alloys.