Deep hole injection assisted by large V-shape pits in InGaN/GaN multiple-quantum-wells blue light-emitting diodes

Li, Yufeng; Yun, Feng; Su, Xilin; Liu, Shuo; Ding, Wen; Hou, Xun

doi:10.1063/1.4896362

Cited by 38 publications

(22 citation statements)

References 35 publications

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“…In the case of electrical injection, holes from the p-GaN layer are directly (path 1) or indirectly (path2) injected into the A-QWs in the direction of the potential energy minimum and undergo radiation recombination with the electrons, as depicted in Figure (f). In other words, the presence of V-pits provides a special path for readier holes to bypass the top QWs near the p-side, and the sandwich designed active region offers a subtle use of these “disadvantages”. We believe that the sandwiched A-QWs have a smaller ground-state energy level, which can induce and limit carrier recombination primarily in the A-QWs.…”

Section: Results and Discussionmentioning

confidence: 99%

Realization of Highly Efficient InGaN Green LEDs with Sandwich-like Multiple Quantum Well Structure: Role of Enhanced Interwell Carrier Transport

Liu

et al. 2018

ACS Photonics

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The potential of multicolor semiconductor electroluminescence in solid-state lighting has been extensively pursued due to the energy-saving and smart-lighting as compared to conventional phosphor-converted white light sources. Here, we demonstrate a highly efficient 525 nm GaN-based green light-emitting diode (LED) with a sandwich-like multiple quantum well (MQW) structure grown on patterned Si(111) substrates. Performance enhancement can be achieved by adjusting the thicknesses of the three quantum barriers close to p-GaN in the interior of the sandwich MQW. Samples A, B, and C, with an optimized barrier thickness of 13, 10, and 8 nm, showed peak external quantum efficiency (EQE) values of 55.6%, 56.2%, and 49.0%, respectively. Under normal working conditions (350 mA, current density 35 A/cm2), the output power, EQE, forward voltage, and dominant wavelength of the sample representing the best performance were 306.0 mW, 37.0%, 2.76 V, and 525 nm, respectively. This work might provide an economically feasible way to realize volume-produce of highly efficient InGaN green LEDs on silicon substrates.

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Section: Results and Discussionmentioning

confidence: 99%

Realization of Highly Efficient InGaN Green LEDs with Sandwich-like Multiple Quantum Well Structure: Role of Enhanced Interwell Carrier Transport

Liu

et al. 2018

ACS Photonics

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“…Such a phenomenon should be attributed to the facilitation of deep hole injection assisted by the large V-pits, as shown in Figure 2 c,d. The V-pits make the current bypass the top QWs and directly inject into the deeper QWs [ 33 , 34 ]. With the ascending current, the bypass effect is weakened, hence leading to the enhancement of the top QWs’ emission, i.e., the green emission.…”

Section: Resultsmentioning

confidence: 99%

Realizing Single Chip White Light InGaN LED via Dual-Wavelength Multiple Quantum Wells

Liu

Zhang

et al. 2022

Materials

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Dual-wavelength multiple quantum wells (MQWs) have great potential in realizing high quality illumination, monolithic micro light-emitting diode (LED) displays and other related fields. Here, we demonstrate a single chip white light indium gallium nitride (InGaN) LED via the manipulation of the dual-wavelength MQWs. The MQWs contain four pairs of blue light-emitting MQWs and one pair of green light-emitting QW. The fabricated LED chips with nickel/gold (Ni/Au) as the current spreading layer emit white light with the injection current changing from 0.5 mA to 80 mA. The chromaticity coordinates of (0.3152, 0.329) closing to the white light location in the Commission International de I’Eclairage (CIE) 1931 chromaticity diagram are obtained under a 1 mA current injection with a color rendering index (CRI) Ra of 60 and correlated color temperature (CCT) of 6246 K. This strategy provides a promising route to realize high quality white light in a single chip, which will significantly simplify the production process of incumbent white light LEDs and promote the progress of high-quality illumination.

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“…Cho et al found that the NR can be suppressed effectively when the energy barrier height is larger than about 80 meV . These researches indicate that V-shaped pits can significantly improve IQE, and several groups ,− have conducted plenty of thorough studies on the mechanism.…”

Section: Introductionmentioning

confidence: 99%

“…By growing InGaN/GaN blue MQWs and measuring the electroluminescence spectra, Li et al investigated the effect that the V-shaped pits have on hole injection. 31 They found that the large V-shaped pits are of great importance for the hole injection depth. By numerical simulation, Quan et al reported that V-shaped pits can promote hole injection and thus enhance the optical performance of the GaN-based MQWs.…”

Section: Introductionmentioning

confidence: 99%

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Mechanism of V-Shaped Pits on Promoting Hole Injection in the InGaN MQWs: First-Principles Investigation

Feng,

Liu,

Zhang

et al. 2024

ACS Omega

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In the InGaN multiple quantum wells (MQWs), V-shaped pits play a crucial role in carrier transport, which directly affects emitting efficiency. First-principles calculations are applied to investigate the formation of the Vshaped pits, and the results indicate that they are inclined to form in the N-rich environment. Meanwhile, we calculate the interfacial electronic properties of the sidewalls of the V-shaped pits with varying indium (In) and magnesium (Mg) compositions. The calculated valence band offset (VBO) of the In 0.3 Ga 0.7 N/Ga 0.94 Mg 0.06 N (0001) is 0.498 eV, while that of the In 0.07 Ga 0.93 N/Ga 0.94 Mg 0.06 N (101̅ 1) is 0.340 eV. The band alignment results show that the valence band edges in the Ga 1−y Mg y N layer are in higher energy than in the In x Ga 1−x N layer. These are in good agreement with the values reported in the previous numerical simulation. Moreover, the calculation of the projected density of states (PDOS) of interfaces discloses that the strong hybridization between the N 2p orbital and the Mg 2p orbital exerts a vital influence on the upward shifts of the valence band edges in the superlattices (SLs). All these results reveal that holes are easier to inject into the quantum wells (QWs) via the sidewall of V-shaped pits rather than the c-plane QWs, providing a theoretical basis for the growth of InGaN MQWs samples containing V-shaped pits.

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Deep hole injection assisted by large V-shape pits in InGaN/GaN multiple-quantum-wells blue light-emitting diodes

Cited by 38 publications

References 35 publications

Realization of Highly Efficient InGaN Green LEDs with Sandwich-like Multiple Quantum Well Structure: Role of Enhanced Interwell Carrier Transport

Realization of Highly Efficient InGaN Green LEDs with Sandwich-like Multiple Quantum Well Structure: Role of Enhanced Interwell Carrier Transport

Realizing Single Chip White Light InGaN LED via Dual-Wavelength Multiple Quantum Wells

Mechanism of V-Shaped Pits on Promoting Hole Injection in the InGaN MQWs: First-Principles Investigation

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