Roles of Al-vacancy complexes on the luminescence spectra of low dislocation density Si-doped AlN grown by halide vapor phase epitaxy
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2025-03-01 |
| Journal | Applied Physics Letters |
| Authors | Shigefusa F. Chichibu, K Kikuchi, Baxter Moody, Seiji Mita, RamĆ³n Collazo |
| Institutions | Adroit Materials (United States), Tohoku University |
| Citations | 3 |
Abstract
Section titled āAbstractāRoles of Al-vacancy (VAl) complexes on the cathodoluminescence (CL) spectra of Si-doped AlN grown by halide vapor phase epitaxy (HVPE) on a physical-vapor-transported (0001) AlN substrate are described, making a connection with the results of positron annihilation measurements. A combination of HVPE and AlN substrate enabled decreasing deleterious carbon concentration and dislocation density, respectively, thus accentuating the influences of VAl-complexes on the luminescence processes. A low-temperature CL spectrum of unintentionally doped AlN exhibited predominant excitonic emissions at around 6 eV and a marginal deep-state emission band at around 3.7 eV that originates from residual carbon (<1016 cmā3) on nitrogen sites (CN). However, the sample was revealed to contain a considerable amount (ā¼1017 cmā3) of vacancy clusters, most likely comprising a VAl and nitrogen-vacancies (VN), namely, VAlVN1ā2, which act as nonradiative recombination centers that decrease overall CL intensity at elevated temperatures. With increasing Si-doping concentration ([Si]), major vacancy species progressively changed from VAlVN1ā2 to VAlON1ā2, where ON is oxygen on N sites, which exhibit other deep-state emission bands ranging from 3.2 to 3.5 eV. Further increase in [Si] gave rise to the formation of donor-compensating defects comprising VAl and Si on the second-nearest-neighbor Al sites (SiAl), abbreviated by VAlāSiAln, which exhibit emission shoulders at around 2.9-3.0 eV. When [Si] exceeded 5 Ć 1018 cmā3, an emission band at around 4.5 eV emerged, which had been ascribed to originate from the nearest-neighbor SiAlCN complexes. Because VAl-complexes, including those containing impurities, are thermally stable, incorporation of vacancies should be blocked at the growth stage.
Tech Support
Section titled āTech SupportāOriginal Source
Section titled āOriginal SourceāReferences
Section titled āReferencesā- 2016 - III-Nitride Ultraviolet Emitters: Technology and Applications