Photoluminescence spectra of Eu-doped GaN with various Eu concentrations

Abstract

Variation of the luminescence spectra of Eu-doped GaN with varying Eu concentration ranging from 0.6to8.0at.% was investigated. Eu-related luminescence originating from the D05-F27 transition of Eu3+ was observed at about 622nm. The luminescence basically consisted of three peaks. The relative intensity of the three peaks changed remarkably at the Eu concentration of around 2.0–3.5at.% which corresponds to a structural phase transition from a single crystalline to a polycrystalline structure. This indicates that the incorporation site of Eu in GaN is very sensitive to the structural properties of the GaN host material.

Incorporation sites and luminescence characterizations of Er-doped GaN grown by molecular beam epitaxy

“…Among the RE elements, Er is more interesting since the Er ions can produce both visible light at 558 nm (green, one of the primary colors) and IR light at 1.54 mm whose spectrum region coincides with the principal low-loss window in the absorption spectrum of aluminosilicate optical fibre. Since, Favennec et al [2] reported that the thermal quenching effect in RE-doped semiconductors decreases with increasing bandgap of the host crystal material, the wide gap semiconductors, such as GaN, have recently received much attention [3][4][5][6][7]. Despite extensive studies, however, the exact nature of the active luminescent centers and the radiation mechanism of Er-doped GaN are still not clear yet.…”

Suppression of concentration quenching of Er-related luminescence in Er-doped GaN

“…Therefore wide gap semiconductor such as GaN has received much attention. [5][6][7][8] However, another barrier called concentration quenching effect 9,10 hinders the developments. The concentration quenching effect means that the RErelated emission intensity increases with RE-concentration up to a certain concentration, and then decreases remarkably.…”

“…[5][6][7][8][9][10] In PL measurement, excitation source is photon, for device application however, electron excitation such as cathodoluminescence ͑CL͒ is more useful than photon excitation. However research reports on the optical properties of Er-doped GaN using CL are not so many as PL.…”

Preparation of europium‐doped GaN and AlGaN films grown by radical‐nitrogen‐assisted compound‐source MBE

“…4(d). For hexagonal-GaN:Eu, PL spectrum due to the 5 D 0 -7 F 2 transitions of Eu 3+ ions is split into three lines [8], corresponding to three PL peaks (α), (β) and (γ). For GaN:Eu, generally, a PL peak at 619 nm (ζ) was not observed.…”