Luminescence properties of pulsed laser deposited Eu:Y₂O₃ thin film phosphors on sapphire substrates

Eu:Y₂O₃ phosphor films were deposited on (0001) sapphire substrates using 248 nm KrF pulse laser to investigate microstructure-property correlations. A slow film growth (60 nm/min) process results in predominantly (222) orientation while a fast film growth (170 nm/min) process results in predominantly (400) orientation of Eu:Y₂O₃ film. With an increase in film thickness from 0.6 μm to 1.2 μm, a 300% increase in brightness has been achieved from Eu:Y₂O₃ films. An increase in substrate temperature during deposition from 700 °C to 800 °C resulted in -40% brighter films. Improvement in brightness from Eu:Y₂O₃ films with the film thickness may be attributed to an increase in roughness while that from substrate temperature may be attributed to a combined effect of increased roughness and improved crystallinity.