Excitation Efficiency and Limitations of the Luminescence of 
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 Ions in 
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Timmerman, Dolf; Mitchell, Brandon; Ichikawa, Shuhei; Tatebayashi, J.; Ashida, Masaaki; Fujiwara, Yoshihiro

doi:10.1103/physrevapplied.13.014044

Cited by 20 publications

(10 citation statements)

References 29 publications

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“…The incorporation of the rare-earth (RE) trivalent europium ions (Eu 3+ ) into III-N layers [16][17][18][19][20][21][22][23] and nanostructures [24][25][26][27][28][29][30][31][32] was proved as an excellent strategy to obtain red emission characterized by the sharp and stable Eu 3+ intra-4f 6 transitions. This approach was successfully implemented for in situ Eu 3+ -doped GaN-based emitting devices [31,[33][34][35][36][37][38], with Eu 3+ -related luminescence external quantum efficiency (EQE) values reaching ~29% at room temperature (RT) and ~48% at 77 K [39]. In order to sustain the EQE value up to RT, it is important to overcome the RE thermal quenching.…”

Section: Introductionmentioning

confidence: 99%

Eu3+ optical activation engineering in Al Ga1-N nanowires for red solid-state nano-emitters

Cardoso

Jacopin

Faye

et al. 2021

Applied Materials Today

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In this work, Eu 3+ -implanted and annealed AlxGa1-xN (0 ≤ x ≤ 1) nanowires (NWs) grown on GaN NW template on Si (111) substrates by plasma-assisted molecular beam epitaxy are studied by µ-Raman, cathodoluminescence (CL), nano-CL, and temperature-dependent steady-state photoluminescence. The preferential location of the Eu 3+ -implanted ions is found to be at the AlxGa1-xN top-section. The recovery of the as-grown crystalline properties is achieved after rapid thermal annealing (RTA). After RTA, the red emission of the Eu 3+ ions is attained for all the samples with below and above bandgap excitation. The 5 D0 → 7 F2 transition is the most intense one, experiencing a redshift with increasing AlN nominal content (x) from GaN to AlN NWs. Moreover, AlN nominal content and annealing temperature alters its spectral shape suggesting the presence of at least two distinct optically active Eu 3+ centers (Eu1 and Eu2). Thermal quenching of the Eu 3+ ion luminescence intensity, I, is found for all the samples from 14 K to 300 K, being the emission of Eu 3+ -implanted AlN NWs after RTA at 1200 ℃ the most stable (I300 K/I14 K ~80%). The GaN/AlN interface in this sample is also found to have a key role in the Eu 3+ optical activation.

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Section: Introductionmentioning

confidence: 99%

Eu3+ optical activation engineering in Al Ga1-N nanowires for red solid-state nano-emitters

Cardoso

Jacopin

Faye

et al. 2021

Applied Materials Today

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“…It is noted here that there are several sharp peaks observed ranging from 617 to 625 nm, which originates from multiple luminescence from Eu 3+ ions with different incorporation centers, which is called "local environment structure" and are assigned as OMVPE 1-8, whose detailed studies have been already reported in our previous publications. [41][42][43][44] In order to clarify the detailed optical characteristics of Eu 3+ ions in the GaN:Eu shell layers, the CL characterization is performed at 15 K from the top view of the single NW. Figure 1f shows the CL spectra at the center and sidewall of the NW which are derived from the CL intensity mapping shown in the inset of Fig.…”

Section: Growth and Optical/structural Characteristics Of Gan:eu/gan Nwsmentioning

confidence: 99%

Formation and Optical Characteristics of GaN:Eu/GaN Nanowires for Applications in Light-Emitting Diodes

Tatebayashi,

Otabara,

Yoshimura

et al. 2023

ECS J. Solid State Sci. Technol.

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This paper reviews our recent research on the formation and optical characteristics of GaN:Eu/GaN nanowires (NWs) by metalorganic vapor phase epitaxy for application in GaN-based red light-emitting diodes (LEDs). Two types of GaN:Eu/GaN NWs with different configurations are introduced, core-shell and axial geometries. The configuration of GaN:Eu layers on GaN core NWs can be controlled by changing the growth conditions, and affects the properties of Eu luminescence in the GaN NWs. Next, the optimization of the p-GaN growth conditions is performed to allow to form the p-GaN shell layers on the NWs with the pedestal of the NWs free from radial overgrowth, resulting in efficient electrical isolation between top and bottom part of the NWs. Then, the fabrication process of the NW LEDs towards future possible realization of flexible devices is established, including an etch-back process of the PDMS membranes to expose the top p-GaN contact layers. Finally, a proto-type of p-GaN/GaN:Eu/n-GaN NW LEDs on sapphire substrates is fabricated to characterize the device characteristics. Sharp red luminescence at room temperature from Eu3+ ions is observed under current injection. These results would pave the way towards the realization of flexible light-emitting devices utilizing NW structures based on compound semiconductors.

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“…Experimentally, the isolated Eu Ga is believed by many to be the dominant Eu 3+ center in Eu-doped GaN samples [5,7,8]. The luminescence center is often characterized by its high relative abundance (up to more than 97% of the incorporated Eu) [9,10], low-efficiency energy transfer from the GaN host to the Eu 3+ 4f -core (the effective excitation cross section ∼1.2 × 10 −17 cm 2 ) [9,10,12], and strong thermal quenching [12]. These descriptions appear to be consistent with the characteristics of the isolated Eu Ga center reported in this work.…”

Section: B Eu-related Defects As Luminescence Centersmentioning

confidence: 99%

“…Experimentally, while the trivalent Eu 3+ ion was found to be predominant in Eu-doped GaN samples and multiple Eu 3+ luminescence centers were observed [4][5][6][7][8][9][10][11][12], the divalent Eu 2+ has also been found or suspected to be present [13][14][15][16][17][18][19][20]. In addition to being of interest for * khang.hoang@ndsu.edu its magnetic properties [14,15,20], Eu 2+ can offer useful luminescence centers in its own right.…”

Section: Introductionmentioning

confidence: 99%

Tuning the valence and concentration of europium and luminescence centers in GaN through co-doping and defect association

Hoang

2020

Preprint

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Defect physics of Eu-doped GaN is investigated using first-principles hybrid density-functional defect calculations. This includes the interaction between the rare-earth dopant and native defects (Ga and N vacancies) and other impurities (O, Si, C, H, and Mg) unintentionally present or intentionally incorporated into the host material. While the trivalent Eu 3+ ion is often found to be predominant when Eu is incorporated at the Ga site in wurtzite GaN, the divalent Eu 2+ is also stable and found to be predominant in a small range of Fermi-level values in the band-gap region. The Eu 2+ /Eu 3+ ratio can be tuned by tuning the position of Fermi level and through defect association. We find co-doping with oxygen can facilitate the incorporation of Eu into the lattice. The unassociated EuGa is an electrically and optically active defect center and its behavior is profoundly impacted by local defect-defect interaction. Among the Eu-related defects, we identify complexes such as EuGa-ON, EuGa-SiGa, EuGa-Hi, EuGa-MgGa, and EuGa-ON-MgGa as efficient defect-related Eu 3+ centers for non-resonant excitation. This work calls for a re-assessment of certain assumptions regarding specific defect configurations previously made for Eu-doped GaN and further investigation into the origin of the photoluminescence hysteresis observed in (Eu,Mg)-doped samples.

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Excitation Efficiency and Limitations of the Luminescence of Eu3+ Ions in GaN

Cited by 20 publications

References 29 publications

Eu3+ optical activation engineering in Al Ga1-N nanowires for red solid-state nano-emitters

Eu3+ optical activation engineering in Al Ga1-N nanowires for red solid-state nano-emitters

Formation and Optical Characteristics of GaN:Eu/GaN Nanowires for Applications in Light-Emitting Diodes

Tuning the valence and concentration of europium and luminescence centers in GaN through co-doping and defect association

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