Ultraviolet electroluminescence from hetero p-n junction between a single ZnO microsphere and p-GaN thin film

Tetsuyama, Norihiro; Fusazaki, Koshi; Mizokami, Y.; Shimogaki, Tetsuya; Higashihata, Mitsuhiro; Nakamura, Daisuke; Okada, Tatsuo

doi:10.1364/oe.22.010026

Cited by 7 publications

(3 citation statements)

References 24 publications

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“…The intense phonon peak at 437.8 cm −1 is known as the signature peak of the wurtzite structure of ZnO. These observations confirm that the undoped and doped spheres crystallize in hexagonal wurtzite ZnO structure with high crystalline quality [31,37]. Raman modes of quartz substrate peak at 126.5 cm −1 , 204.9 cm −1 , 262.1 cm −1 , 353.2 cm −1 , 401.8 cm −1 and 465.4 cm −1 .…”

Section: Morphological and Structural Analysissupporting

confidence: 62%

Realization of sharp visible WGM lasing from Sm³⁺ :ZnO micro-spheres fabricated by laser ablation technique

Fabitha

Wakiyama

Oshima

et al. 2020

J. Phys. D: Appl. Phys.

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In this paper, the whispering gallery mode lasing from Sm 3+ doped ZnO micro-spheres operating in the visible wavelength range 550-750 nm is studied. Highly smooth and crystalline Sm 3+ :ZnO micro-spheres of various diameters were synthesized by simple laser ablation of sintered target in air. The dopant concentration has been restricted within the solid solubility limit of 1 mol%. The Sm 3+ ion substitution in ZnO matrix results in the formation of inter-band levels by the characteristic 4f level of Sm 3+ in the forbidden gap of ZnO. Thus, when the micro-spheres are excited with 488 nm, four major visible emissions associated with Sm 3+ f − f transitions namely, transitions from 4 G 5/2 to its low-lying multiplets of 6 H J (J = 5/2, 7/2, 9/2 and 11/2), are obtained. These emissions are coupled to the WGMs of the Sm 3+ :ZnO micro-cavity resulting in sharp resonances in the visible region. Interestingly, the resonances are found to be lasing above lower pumping powers. The Q-factor obtained is of the order of 10 3 for spheres of size ranging 1.8-10.2 µm. The best Q-factor obtained is 3744 for 561.61 nm peak (FWHM 0.15 nm) from 8 µm sphere. These results would find a place in visible range lasing and sensor applications.

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Section: Morphological and Structural Analysissupporting

confidence: 62%

Realization of sharp visible WGM lasing from Sm³⁺ :ZnO micro-spheres fabricated by laser ablation technique

Fabitha

Wakiyama

Oshima

et al. 2020

J. Phys. D: Appl. Phys.

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“…The ZnO microstructure as a natural WGM microcavity does not require external gain media and complex processing. Recent reports have shown that ZnO WGM microcavities can exhibit ultraviolet electroluminescence 20 as well as interfacial refractive index sensing 21 and ultrasensitive dopamine detection by utilizing its high-quality resonance. 22 However, ZnO microspheres are usually difficult to fabricate because of the wurtzite crystal structure.…”

Section: Instructionmentioning

confidence: 99%

Controllable Fabrication of ZnO Microspheres for Whispering Gallery Mode Microcavity

Liu

Zhu

et al. 2018

Crystal Growth & Design

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Whispering gallery mode (WGM) microcavity made of ZnO microspheres is an ideal platform for photonic integration and optical biological detection. However, the fabrication and the formation mechanism of ZnO microspheres is still challenging. In this paper, we present a controllable fabrication strategy to obtain zinc oxide (ZnO) microspheres with smooth surface, good crystallinity, and excellent optical properties for improved WGM lasing performance by taking advantage of the cooperative process between reactants, annealing, and metal nanoparticles decoration. The synergic effect between the hexamethylenetetramine (C6H12N4) and citrate was experimentally observed on the formation of ZnO microspheres. Their crystallinity and surface flatness can be improved by gradually decreasing the heating rate. Due to the electron transfer process in the metal/semiconductor hybrid structure assisted by the localized surface plasmon resonance, Au NPs can match well with the photon energy of the defect emission of ZnO microsphere and induced a 1 order of magnitude increase in lasing intensity compared to the bare one. Our results hold promise for the application of ZnO microspheres in the construction of UV laser and WGM sensing technology.

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“…In addition, ZnO nano= microstructures have attracted considerable attention because of their high crystalline quality and unique structures such as nanowires, 1,2) nanosheets, 3,4) nanorods, [5][6][7] nanowalls, [8][9][10][11] and microspheres. [12][13][14][15] For the development ZnO-based devices, p-type ZnO and n-type ZnO are necessary. However, ZnO is typically n-type and doping for acceptors in ZnO nano=microstructures is difficult owing to crystal defects such as oxygen vacancies and residual electrons.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of Sb-doped ZnO microspheres by pulsed laser ablation

Nagasaki

Shimogaki

Tanaka

et al. 2016

Jpn. J. Appl. Phys.

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We succeeded in synthesizing antimony (Sb)-doped zinc oxide (ZnO) microspheres by ablating a sintered ZnO target containing Sb in air. The structural properties of the microspheres were investigated by Raman scattering studies. The Zn–Sb related local vibrational mode (LVM) was detected around 238 cm−1. Room-temperature photoluminescence (PL) properties of the microspheres were investigated under cw and pulsed laser excitations, and ultraviolet (UV) emission and whispering-gallery-mode (WGM) lasing were observed from the microspheres. Furthermore, a p–n heterojunction was formed between a single Sb-doped ZnO microsphere and an n-Al-doped ZnO thin film, and a good rectifying property with a turn-on voltage of approximately 1.8 V was observed in the current–voltage (I–V) characteristics across the junction.

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Ultraviolet electroluminescence from hetero p-n junction between a single ZnO microsphere and p-GaN thin film

Cited by 7 publications

References 24 publications

Realization of sharp visible WGM lasing from Sm³⁺ :ZnO micro-spheres fabricated by laser ablation technique

Realization of sharp visible WGM lasing from Sm³⁺ :ZnO micro-spheres fabricated by laser ablation technique

Controllable Fabrication of ZnO Microspheres for Whispering Gallery Mode Microcavity

Synthesis and characterization of Sb-doped ZnO microspheres by pulsed laser ablation

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Ultraviolet electroluminescence from hetero p-n junction between a single ZnO microsphere and p-GaN thin film

Cited by 7 publications

References 24 publications

Realization of sharp visible WGM lasing from Sm3+ :ZnO micro-spheres fabricated by laser ablation technique

Realization of sharp visible WGM lasing from Sm3+ :ZnO micro-spheres fabricated by laser ablation technique

Controllable Fabrication of ZnO Microspheres for Whispering Gallery Mode Microcavity

Synthesis and characterization of Sb-doped ZnO microspheres by pulsed laser ablation

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Realization of sharp visible WGM lasing from Sm³⁺ :ZnO micro-spheres fabricated by laser ablation technique

Realization of sharp visible WGM lasing from Sm³⁺ :ZnO micro-spheres fabricated by laser ablation technique