Evolution and control of dislocations in GaN grown on cone-patterned sapphire substrate by Metal Organic Vapor PhaseEpitaxy

Tao, Y. B.; Yu, Tongjun; Yang, Zhiyuan; Ling, Dan; Wang, Yan; Chen, Z.Z.; Zhi‐Jian, Yang; Zhang, G.Y.

doi:10.1016/j.jcrysgro.2010.09.072

Cited by 14 publications

(4 citation statements)

References 16 publications

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“…Using the PSS reduces the amount of dislocation density in the GaN layer and enhances the LEE in the LED chip, thus improving the EQE. 21,22 A 20 nm-thick GaN nucleation layer, a 1.5 mm-thick undoped GaN layer, a 2 mm-thick n-type GaN layer, 5-pairs InGaN/GaN multiple-quantum-well (MQW) active layers, and a 200 nm-thick p-type GaN layer were subsequently grown on PSS. Using the conventional LED fabrication technique, we produced a full chip with ITO as the transparent top conductive layer and Cr/Au as the p-n-type electrode, as shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Light-extraction enhancement of a GaN-based LED covered with ZnO nanorod arrays

et al. 2014

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We investigate the mechanism of light extraction enhancement of a GaN-based light-emitting diode (LED) grown on patterned sapphire substrate (PSS), that has ZnO nanorod arrays (NRAs) fabricated on top of the device using the hydrothermal method. We found that the light output power of the LED with ZnO NRAs increases by approximately 30% compared to the conventional LED without damaging the electrical properties of the device. We argue that the gradual decrease of the effective refractive index, which is caused by the fabrication of ZnO NRAs, is the mechanism of the observed improvement. Our argument is confirmed by cross-sectional confocal scanning electroluminescence microscopy (CSEM) and the theoretical simulations, where we observed a distinct increase of the transmission at the interface between LED and air at the operation wavelength of the LED. In addition, the plane-view CSEM results indicate that ZnO NRAs, which were grown on the bare p-type GaN layer as an electrical safety margin area, also contribute to the enhanced light output power of the LED, which indicate further enhancement is manifested even in the optically ineffective sacrificial area.

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Section: Resultsmentioning

confidence: 99%

Light-extraction enhancement of a GaN-based LED covered with ZnO nanorod arrays

et al. 2014

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“…Recently, excellent progress has been made in simultaneously improving both the LEE and IQE. Methods include using patterned sapphire substrates (PSS) with a variety of proposed shapes [22], [23], novel epitaxial nanostructures [24]- [26], and GaN air-voids structures [27]- [30]. Those results demonstrate the superior light output power and the lower threading dislocation density.…”

Section: Efficiency Improvement Of Blue Leds Using a Gan Burried Air mentioning

confidence: 99%

Efficiency Improvement of Blue LEDs Using a GaN Burried Air Void Photonic Crystal With High Air Filling Fraction

Liu

Charlton

Lin³

et al. 2014

IEEE J. Quantum Electron.

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In this paper, we investigate the efficiency enhancement of blue InGaN/GaN light-emitting diodes (LEDs) by incorporating a burried air void photonic crystal (BAVPC) layer within the epitaxial structure. As compared with the conventional patterned sapphire substrate (C-PSS) LEDs and flat sapphire substrate LEDs with BAVPC, the fabricated patterned sapphire substrate (PSS) LEDs with BAVPC exhibit the lowest full-width at half-maximum of (002) and (102) diffraction peaks, the highest light output power of 20.6 mW, and the highest external quantum efficiency of 37.4%. Remarkable performance improvement in the PSS LED with BAVPC is attributed to the better epitaxial quality with threading dislocations terminated by the BAVPC and the higher scattering at interface between GaN and air-void. By positioning the BAVPC directly below the multiple quantum wells (MQWs), it would cause the reduction in the number of trapped optical modes. The methodology optically isolates the MQWs from the underlying substrate and increases the optical output power. Moreover, threading dislocations are significantly suppressed using the BAVPC with high air filling fraction of ∼50%. It is well proposed that this methodology provides a promising alternative to C-PSS LEDs. Index Terms-Light-emitting diode (LED), burried air void photonic crystal (BAVPC), patterned sapphire substrate (PSS), nanoimprint lithography (NIL).

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“…High-quality GaN has been developed via epitaxial lateral overgrowth (ELO) and its derivatives such as pendeo-epitaxy (PE) [12] and cantilever epitaxy (CE) [13,14]; however, these multi-step processing techniques lead to very high production costs [15][16][17]. Alternatively, the crystal quality of GaN was improved by employing a sapphire substrate masked with the serpentine channel.…”

Section: Introductionmentioning

confidence: 99%

Effects of InGaN-interlayer on closed stripes of GaN grown by serpentine channel patterned sapphire substrate

Khan¹,

Lei²,

Chen³

et al. 2022

Mater. Res. Express

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Gallium nitride (GaN) is a widely investigated semiconductor owing to its fascinating features suitable for a plethora of optoelectronic applications; nevertheless, well-controlled growth of this material remains a challenge. In this work, the crystal quality of GaN grown by serpentine channel patterned sapphire substrates (SCPSS) is improved via introducing indium gallium nitride (InGaN) as an interlayer (IL). The closed stripes of GaN are grown by the modified design of SCPSS. Our results show that the crystal quality of GaN developed in the form of closed stripes is superior than conventionally grown counterpart. Transmission electron microscopy (TEM) revealed that the design of SCPSS controls all threading dislocations (TDs) while cathodoluminescence (CL) analysis showed that the closed stripes are relaxed and produce many TDs. Therefore, further control over the TDs was achieved by InGaN-IL. During the growth process, the temperature of GaN was reduced and 20 nm thick InGaN-IL was added at 800 ℃. The detailed characterization of our developed samples indicated that the additional use of InGaN-IL in SCPSS is very effective for improving the crystal quality of GaN. We anticipate that our findings will improve the current understanding about the growth of high-quality GaN towards efficient optoelectronic devices.

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Evolution and control of dislocations in GaN grown on cone-patterned sapphire substrate by Metal Organic Vapor PhaseEpitaxy

Cited by 14 publications

References 16 publications

Light-extraction enhancement of a GaN-based LED covered with ZnO nanorod arrays

Light-extraction enhancement of a GaN-based LED covered with ZnO nanorod arrays

Efficiency Improvement of Blue LEDs Using a GaN Burried Air Void Photonic Crystal With High Air Filling Fraction

Effects of InGaN-interlayer on closed stripes of GaN grown by serpentine channel patterned sapphire substrate

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