Luminescence properties of MOCVD grown Al0.2Ga0.8N layers implanted with Tb

• Autor(a) principal: Rodrigues, J.
• Data de Publicação: 2019
• Outros Autores: Fialho, M., Magalhães, S., Lorenz, K., Alves, E., Monteiro, T.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/37387
• topic: AlxGa1-xN; Tb3+; Ion implantation; Photoluminescence; Yellow luminescence

AlxGa1-xN (x = 0.20) layers grown on (0001) sapphire substrates by metal organic chemical vapour deposition were implanted with terbium (Tb) ions at 150 keV with a fluence of 7 × 1014 Tb cm−2 at different temperatures. After thermal annealing, all layers evidenced the Tb-related 5D4-7FJ intra-4f8 transitions, demonstrating an enhancement of their intensity with increasing implantation temperature. A detailed spectroscopic analysis of the optical properties of these layers was conducted using luminescence techniques. An atypical behaviour for the relative intensity of both the broad visible band and the intraionic lines was found as a function of temperature and its origin is discussed based on potential fluctuation phenomena and energy transfer processes. The 5D4-7FJ intra-4f8 transitions exhibit thermal population with increasing temperature between ∼100 K and ∼200–230 K, with a subsequent decrease up to RT due to further competitive non-radiative recombination paths. The values calculated for the population energies of each sample are in good agreement with the ones obtained for the activation energies of the de-excitation of the yellow broad band also present in the spectra, suggesting a correlation between the host defect de-excitation processes and the population of the ion emitting levels.