Overshoot effects of electron on efficiency droop in InGaN/GaN MQW light-emitting diodes

Huang, Yang; Liu, Zhiqiang; Yi, Xiaoyan; Wu, Shaoteng; Yuan, Guodong; Wang, Junxi; Li, Jinmin

doi:10.1063/1.4948511

Cited by 5 publications

(5 citation statements)

References 29 publications

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“…In doing so, this approach ensures that the carriers populate the wells and that transmission properties can be studied efficiently, without having to include numerically expensive electron-phonon coupling effects, which can be addressed in future studies. We note that similar approaches have been used in the literature to study the ballistic transport properties in InGaN MQWs, however, without considering the impact of alloy fluctuations and thus connected carrier localization effects [26][27][28].…”

Section: Theoretical Frameworkmentioning

confidence: 99%

Impact of random alloy fluctuations on inter-well transport in InGaN/GaN multi-quantum well systems: an atomistic non-equilibrium Green’s function study

O'Donovan¹,

Luisier²,

O’Reilly³

et al. 2020

J. Phys.: Condens. Matter

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Recent experimental studies indicate the presence of ballistic hole transport in InGaN multi quantum well (MQW) structures. Widely used drift–diffusion models cannot give insight into this question, since quantum mechanical effects, such as tunneling, are not included in such semi-classical approaches. Also atomistic effects, e.g. carrier localization effects and built-in field variations due to (random) alloy fluctuations, are often neglected in ballistic transport calculations on InGaN quantum well systems. In this work we use atomistic tight-binding theory in conjunction with a non-equilibrium Green’s function approach to study electron and hole ballistic transport in InGaN MQW systems. Our results show that for electrons the alloy microstructure is of secondary importance for their ballistic transport properties, while for hole transport the situation is different. We observe for narrow barrier widths in an InGaN MQW system that (random) alloy fluctuations give rise to extra hole transmission channels when compared to a virtual crystal description of the same system. We attribute this effect to the situation that in the random alloy case, k ∥-vector conservation is broken/relaxed and therefore the ballistic hole transport is increased. However, for wider barrier width this effect is strongly reduced, which is consistent with experimental studies. Our findings also provide a possible explanation for recent experimental results where alloying the barrier between the wells leads to enhanced ballistic (hole) transport in InGaN MQW systems.

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Section: Theoretical Frameworkmentioning

confidence: 99%

Impact of random alloy fluctuations on inter-well transport in InGaN/GaN multi-quantum well systems: an atomistic non-equilibrium Green’s function study

O'Donovan¹,

Luisier²,

O’Reilly³

et al. 2020

J. Phys.: Condens. Matter

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“…This is also useful to improve the holes injection efficiency. At the same time, In 0.03 GaN/GaN superlattice between n-GaN and MQWs can help to improve the surface roughness and reduce the density of the V-defects, which is normally found in InGaN/GaN MQWs [20][21][22] . What is more, about the 230 meV energy barrier as shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Performance improvement of light-emitting diodes with double superlattices confinement layer

et al. 2018

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In this study, the effect of double superlattices on GaN-based blue light-emitting diodes (LEDs) is analyzed numerically. One of the superlattices is composed of InGaN/GaN, which is designed before the multiple quantum wells (MQWs). The other one is AlInGaN/AlGaN, which is inserted between the last QB (quantum barriers) and p-GaN. The crucial characteristics of double superlattices LEDs structure, including the energy band diagrams, carrier concentrations in the active region, light output power, internal quantum efficiency, respectively, were analyzed in detail. The simulation results suggest that compared with the conventional AlGaN electron-blocking layer (EBL) LED, the LED with double superlattices has better performance due to the enhancement of electron confinement and the increase of hole injection. The double superlattices can make it easier for the carriers tunneling to the MQWs, especially for the holes. Furthermore, the LED with the double superlattices can effectively suppress the electron overflow out of multiple quantum wells simultaneously. From the result, we argue that output power is enhanced dramatically, and the efficiency droop is substantially mitigated when the double superlattices are used.

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“…The carriers trapped in the QWs can either recombine with the rate of f rec or escape the QWs, causing carrier leakage out of the active region at a rate of f leak . The leakage is caused by the thermionic emission, carrier overflow, and other mechanisms [45].…”

Section: Dynamic Photon Generation Modelsmentioning

confidence: 99%

Characterization of dynamic distortion in LED light output for optical wireless communications

et al. 2021

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Overshoot effects of electron on efficiency droop in InGaN/GaN MQW light-emitting diodes

Cited by 5 publications

References 29 publications

Impact of random alloy fluctuations on inter-well transport in InGaN/GaN multi-quantum well systems: an atomistic non-equilibrium Green’s function study

Impact of random alloy fluctuations on inter-well transport in InGaN/GaN multi-quantum well systems: an atomistic non-equilibrium Green’s function study

Performance improvement of light-emitting diodes with double superlattices confinement layer

Characterization of dynamic distortion in LED light output for optical wireless communications

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