Engineering visible light emitting point defects in Zr-implanted polycrystalline AlN films

Abstract

We have investigated the impact of thermal annealing gaseous atmosphere of argon, nitrogen and forming gas on the structural and optical properties of thin polycrystalline AlN films subjected to high-energy zirconium ions implantation. X-ray diffraction, Raman spectroscopy, scanning electron microscopy and atomic force microscopy measurements show that the structural and morphological properties of the Zr-implanted AlN films depends on the annealing gaseous environment. The post-implantation annealing under argon atmosphere yields the lowest structured surface roughness with increased grain size. Photoluminescence spectroscopy revealed multiple point defects and defect complexes related emission bands in the visible range. A series of absorption bands have been observed using photoluminescence excitation spectroscopy. The origin of the emission or absorption bands is identified and attributed to various types of point defects and defect complexes, theoretically reported for AlN. New emission and absorption peaks at 1.7 eV (730 nm) and 2.6 eV (466 nm), respectively, have been identified and attributed to the (ZrAl-VN) 0 defect complexes.