Evidence of new point defects optical features in Zr-implanted polycrystalline AlN films

Recently negatively charged nitrogen vacancies and large metal ion (Zr, Hf) – vacancy pairs in aluminum nitride (AlN) have been theoretically reported as promising qubit candidates [1]. In this work, 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 implantation of zirconium ions. The results from structural characterizations suggest that the structural and morphological properties of the Zr-implanted AlN films depend on the annealing gaseous environment. A series of absorption and emission bands were observed using photoluminescence spectroscopy (PL) and photoluminescence excitation spectroscopy (PLE). 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 (Zr_Al-V_N)⁰ defect complexes.
[1] Seo, Hosung, et al. "Designing defect-based qubit candidates in wide-gap binary semiconductors for solid-state quantum technologies." Physical Review Materials 1.7 (2017): 075002.