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 “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2025-03-01 |
| Journal | Applied Physics Letters |
| Authors | Shigefusa F. Chichibu, K Kikuchi, Baxter Moody, Seiji Mita, Ramón Collazo |
| Institutions | National Institute of Advanced Industrial Science and Technology, Tohoku University |
| Citations | 3 |
Abstract
Section titled “Abstract”Roles 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 cm−3) on nitrogen sites (CN). However, the sample was revealed to contain a considerable amount (∼1017 cm−3) of vacancy clusters, most likely comprising a VAl and nitrogen-vacancies (VN), namely, VAlVN1−2, 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 VAlVN1−2 to VAlON1−2, 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 VAl−SiAln, which exhibit emission shoulders at around 2.9-3.0 eV. When [Si] exceeded 5 × 1018 cm−3, 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 “Tech Support”Original Source
Section titled “Original Source”References
Section titled “References”- 2016 - III-Nitride Ultraviolet Emitters: Technology and Applications