Current status for light-emitting diode with Eu-doped GaN active layer grown by MBE

Wakahara, Akihiro; Sekiguchi, Hiroto; Okada, Hiroshi; Takagi, Yasufumi

doi:10.1016/j.jlumin.2012.02.001

Cited by 28 publications

(20 citation statements)

References 38 publications

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“…In 2009, a GaN:Eu red LED was demonstrated using MOVPE, for the first time . In keeping with this report, some reports on red and infrared LEDs with GaN:Eu and InGaN:Er layers as active layers have been mentioned . Recently, light outputs of these LEDs reached more than 1 mW .…”

Section: Introductionsupporting

confidence: 54%

Self-Organized Eu-Doped GaN Nanocolumn Light-Emitting Diode Grown by RF-Molecular-Beam Epitaxy

Sukegawa

Sekiguchi

Matsuzaki

et al. 2018

Phys. Status Solidi A

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High-concentration doping of Eu ions working as luminescent centers in GaN is required to improve light output of optical devices. GaN nanocolumns can be used to achieve high crystallinity in high-concentration Eudoped GaN (GaN:Eu). In this study, optical properties of a GaN:Eu nanocolumn grown by RF-plasma-assisted molecular-beam epitaxy (RF-MBE) are investigated and GaN:Eu nanocolumn light-emitting diodes (LEDs) are demonstrated. Suppression of yellow luminescence and concentration quenching of PL intensity are observed at RT for GaN:Eu nanocolumns. When the effect of Eu concentration on optical properties is analyzed using rate equation, an increase in the Eu concentration is observed to affect 5 D 0 lifetime corresponding to back transfer, and not the effective cross-section corresponding to transfer efficiency. Based on these results, GaN:Eu nanocolumn LEDs are fabricated on an n-type (111) Si substrate. Clear rectification characteristics and sharp red luminescence are observed. The light output increases with increasing Eu concentration up to a concentration of 6 Â 10 20 cm À3 . These results suggested that GaN:Eu nanocolumns provide feasible crystal to realize novel optical devices.

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Section: Introductionsupporting

confidence: 54%

Self-Organized Eu-Doped GaN Nanocolumn Light-Emitting Diode Grown by RF-Molecular-Beam Epitaxy

Sukegawa

Sekiguchi

Matsuzaki

et al. 2018

Phys. Status Solidi A

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“…Our group and other groups have also demonstrated the selective activation of one site and enhanced the Eu 3þ luminescence in Mg-codoped GaN:Eu (GaN:Eu, Mg) by MBE and OMVPE. [24][25][26] However, the mechanism of emission enhancement by Mg codoping has not yet been clarified.…”

Section: Introductionmentioning

confidence: 99%

Emission enhancement mechanism of GaN:Eu by Mg codoping

Sekiguchi

Takagi

Otani

et al. 2013

Journal of Applied Physics

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Mg codoping into Eu-doped GaN strongly affects the two dominant optical sites A (620.3 nm) and B (622.3 nm) and dramatically improves the optical characteristics obtained from Eu 3þ ions. To clarify the mechanism of the enhanced emission, the effects of the Mg concentration on the excitation and emission processes were evaluated by considering the excitation power dependence of photoluminescence (PL) and time-resolved PL at various temperatures. The excitation cross section r ex , which reflected the excitation process, did not depend on the Mg concentration but strongly on the optical site, which was attributed to the different energy transfer processes of the two optical sites. r ex for site A was three times larger than that for site B, indicating higher excitation efficiency for site A. Mg codoping dramatically increased the number of Eu ions in site A that remain active at room temperature (RT) and the 5 D 0 lifetime at RT, indicating the suppression of nonradiative components during the emission process. Therefore, the optical properties were markedly enhanced by Mg codoping. V C 2013 American Institute of Physics. [http://dx.

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“…The intra-4f electron transition in rare-earth ions is atomically sharp, and the temperature drift of the emission wavelength is negligible because of the occupied outer orbitals. As a host material for rare-earth elements with emission over a wide wavelength range, wide-band gap nitride semiconductors such as AlN, GaN, and Al x Ga 1Àx N have been explored [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] for developing electroluminescence devices 10,22-24 and electron-excitation devices. 25,26 In particular, for UV rareearth phosphors, lightly Gd-doped AlN or Al x Ga 1Àx N is known to emit an atomically sharp line at approximately 3.9 eV (318 nm).…”

Section: Introductionmentioning

confidence: 99%

Thermal annealing effects on ultra-violet luminescence properties of Gd doped AlN

Ishizu

Tsuji

Harada

et al. 2015

Journal of Applied Physics

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We studied energy transfer from AlN to doped Gd 3þ ions as a function of the post-thermal annealing temperature. Gd-doped AlN thin films were deposited on fused-silica substrates using a reactive radio-frequency magnetron sputtering technique. The film is a c-axis oriented polycrystal. The intraorbital electron transition in Gd 3þ showed an atomically sharp luminescence at 3.9 eV (318 nm). The photoluminescence (PL) excitation spectrum exhibited a resonant peak, indicating efficient energy transfer from the host AlN crystal to Gd 3þ ions. The PL intensity increases approximately ten times by thermal annealing. The PL decay lifetime becomes long with annealing, and mid-gap luminescence relating to the crystal defects in AlN was also found to be reduced by annealing. These results suggest that energy dissipation of excited carriers in AlN was suppressed by annealing, and the efficiency of energy transfer into Gd 3þ was improved. V C 2015 AIP Publishing LLC.

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Current status for light-emitting diode with Eu-doped GaN active layer grown by MBE

Cited by 28 publications

References 38 publications

Self-Organized Eu-Doped GaN Nanocolumn Light-Emitting Diode Grown by RF-Molecular-Beam Epitaxy

Self-Organized Eu-Doped GaN Nanocolumn Light-Emitting Diode Grown by RF-Molecular-Beam Epitaxy

Emission enhancement mechanism of GaN:Eu by Mg codoping

Thermal annealing effects on ultra-violet luminescence properties of Gd doped AlN

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