Deep ultraviolet light-emitting diodes based on a well-ordered AlGaN nanorod array

Zhang, Liang; Guo, Yanan; Yan, Jianchang; Wu, Qingwen; Lu, Yi; Wu, Zheng; Gu, Wen; Wei, Xianhua; Wang, Junxi; Li, Jinmin

doi:10.1364/prj.7.000b66

Cited by 27 publications

(24 citation statements)

References 34 publications

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“…[3][4][5][6] For instance, >2.6 times improvement of the EQE has been demonstrated for top-down etched nanowires in comparison to the same wafer processed with planar geometry. 7 Most of the research efforts on nanowires for UV emission refer to structures synthesized by molecular beam epitaxy (MBE). The directionality of the MBE technique allows growing complex axial heterostructures.…”

Section: ■ Introductionmentioning

confidence: 99%

UV Emission from GaN Wires with m-Plane Core–Shell GaN/AlGaN Multiple Quantum Wells

Grenier

Finot

Jacopin

et al. 2020

ACS Appl. Mater. Interfaces

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The present work reports high quality non-polar GaN/Al0.6Ga0.4N multiple quantum wells (MQWs) grown in core-shell geometry by metalorganic vapor phase epitaxy on the m-plane sidewalls of ̅ -oriented hexagonal GaN wires. Optical and structural studies reveal UV emission originating from the core-shell GaN/AlGaN MQWs. Tuning the mplane GaN QW thickness from 4.3 to 0.7 nm leads to a shift of the emission from 347 to 292 nm, consistent with Schrödinger-Poisson calculations. The evolution of the luminescence with temperature displays signs of strong localization, especially for samples with thinner GaN QWs and no evidence of quantum confinement Stark effect, as expected for non-polar m-plane surfaces. The internal quantum efficiency derived from the photoluminescence intensity ratio at low and room temperature is maximum (~7.3 %) for 2.6 nm-thick quantum wells, emitting at 325 nm and shows a large drop for thicker QWs. An extensive study of the PL quenching with temperature is presented.Two non-radiative recombination paths are activated at different temperatures. The low temperature path is found to be intrinsic to the heterostructure, whereas the process that dominates at high temperature depends on the QW thickness and is strongly enhanced for QWs larger than 2.6 nm, causing a drop of the internal quantum efficiency.

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Section: ■ Introductionmentioning

confidence: 99%

UV Emission from GaN Wires with m-Plane Core–Shell GaN/AlGaN Multiple Quantum Wells

Grenier

Finot

Jacopin

et al. 2020

ACS Appl. Mater. Interfaces

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“…Dot-type nanostructures are very useful in deep ultraviolet light-emitting diodes and electron-optical detectors. [25,26] As shown in Figure 4a, dot arrays with different radii were prepared by laser-assisted thermal exposure lithography. The feature size was varied from 90 nm to 2.3 μm and the height was %90 nm.…”

Section: Resultsmentioning

confidence: 99%

“…This indicates that the feature size increases with increase in laser pulse duration. In addition, as shown in Figure 2a,b, when the laser power or pulse duration further increases to 6.4 mW or 120 ns, the peak temperature of the film exceeds its melting point (540 °C), [ 25 ] which corresponds to the molten ablation, and it cannot obtain the qualified micro/nanostructures. Therefore, one needs to limit the peak temperature to above the crystallization temperature and below the ablation temperature of the heat‐mode resist film to achieve correct thermal exposure.…”

Section: Resultsmentioning

confidence: 99%

Laser‐Assisted Thermal Exposure Lithography: Arbitrary Feature Sizes

et al. 2021

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In traditional optical exposure lithography, the feature size is restricted by the Abbe limit, and it is difficult to obtain patterns with a feature size smaller or larger than the optical spot itself. Herein, a laser-assisted thermal exposure lithography technique is reported where the feature size can be arbitrarily tuned and changed, and is not limited to the spot size. The minimum feature size of the obtained patterns is 90 nm, which is %1/7 of the laser spot size (0.62 μm). The corresponding aspect ratio is %1:1. The maximum feature size is 2.7 μm, which is %30 times the minimum feature size. A variety of multiscale and multifunctional structures with different feature sizes are obtained successfully through a highspeed laser-assisted thermal exposure system, where the writing speed is more than 10 m s À1 . This method offers a pathway for direct laser writing with arbitrary feature sizes, high throughput, and low cost.

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“…The nanorod LED forms quasi waveguide structure, and the light emitted from the MQWs of one individual nanorod can couple into the vertically directed guided mode [28], or couple into adjoining nanorods to again form vertically directed guided mode, leading to the increased chance of photons escaping from the substrate side. Moreover, the Bragg diffraction induced by the highly ordered nanorod LED also increases the photons extracted from the sidewall in the vertical direction [29]. Still having a bit is, the downsize with the p-GaN leads to the decrease with the absorption of photons, and thereby increases the escaping probability of the photon from the inside of the chip [26].…”

Section: Resultsmentioning

confidence: 99%

The Optical Properties of InGaN/GaN Nanorods Fabricated on (-201) β-Ga2O3 Substrate for Vertical Light Emitting Diodes

Zhao

Wang

et al. 2021

Photonics

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We fabricated InGaN/GaN nanorod light emitting diode (LED) on (-201) β-Ga2O3 substrate via the SiO2 nanosphere lithography and dry-etching techniques. The InGaN/GaN nanorod LED grown on β-Ga2O3 can effectively suppress quantum confined Stark effect (QCSE) compared to planar LED on account of the strain relaxation. With the enhancement of excitation power density, the photoluminescence (PL) peak shows a large blue-shift for the planar LED, while for the nanorod LED, the peak position shift is small. Furthermore, the simulations also show that the light extraction efficiency (LEE) of the nanorod LED is approximately seven times as high as that of the planar LED. Obviously, the InGaN/GaN/β-Ga2O3 nanorod LED is conducive to improving the optical performance relative to planar LED, and the present work may lay the groundwork for future development of the GaN-based vertical light emitting diodes (VLEDs) on β-Ga2O3 substrate.

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Deep ultraviolet light-emitting diodes based on a well-ordered AlGaN nanorod array

Cited by 27 publications

References 34 publications

UV Emission from GaN Wires with m-Plane Core–Shell GaN/AlGaN Multiple Quantum Wells

UV Emission from GaN Wires with m-Plane Core–Shell GaN/AlGaN Multiple Quantum Wells

Laser‐Assisted Thermal Exposure Lithography: Arbitrary Feature Sizes

The Optical Properties of InGaN/GaN Nanorods Fabricated on (-201) β-Ga2O3 Substrate for Vertical Light Emitting Diodes

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