Improvement of efficiency of GaN-based polarization-doped light-emitting diodes grown by metalorganic chemical vapor deposition

Zhang, L.; Wei, Xiang; Liu, N. X.; Lu, Hai; Zeng, Jia-Ming; Wang, J. X.; Zeng, Yiping; Li, J. M.

doi:10.1063/1.3601469

Cited by 35 publications

(14 citation statements)

References 15 publications

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“…15,16 This results in large electron leakage and inefficient injection of holes at high injection current, which are believed to significantly contribute to the efficiency droop in GaN-based MQW LEDs. As a result, several designs of EBL have been suggested, such as graded EBL, [17][18][19] InAlN EBL, 20 AlGaInN EBL, 21 and AlGaN/GaN superlattice EBL, 22 to improve its effectiveness. However, it is usually difficult to grow these EBLs with high crystal quality.…”

Section: Introductionmentioning

confidence: 99%

Efficiency enhancement of blue InGaN/GaN light-emitting diodes with an AlGaN-GaN-AlGaN electron blocking layer

Xia¹,

Li²,

Lü

et al. 2012

Journal of Applied Physics

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Blue InGaN/GaN multiple quantum well light-emitting diodes (LEDs) with the conventional AlGaN and AlGaN-GaN-AlGaN (AGA) electron blocking layer (EBL) are investigated numerically. The simulation results show that the LEDs with the AGA EBL exhibit much higher output power and smaller efficiency droop at high current as compared to those with the conventional EBL due to the enhancement of the electron confinement and improvement of the hole injection from p-type region, which are induced by the strong electrostatic fields and tunneling effect in the AGA EBL.

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Section: Introductionmentioning

confidence: 99%

Efficiency enhancement of blue InGaN/GaN light-emitting diodes with an AlGaN-GaN-AlGaN electron blocking layer

Xia¹,

Li²,

Lü

et al. 2012

Journal of Applied Physics

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“…The latter was due to modification of the LD band diagram originated from the polarization charge distributed in the EBL. Experimentally, the EBL of such a design embedded into a blue LED structure enabled improvement of its efficiency and series resistance . A similar EBL used in a deep‐UV LED structure provided more than twofold improvement of its emission efficiency .…”

Section: Introductionmentioning

confidence: 99%

Polarization doping for III-nitride optoelectronics

Khokhlev¹,

Bulashevich²,

Karpov³

2013

Phys. Status Solidi A

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The paper considers new opportunities for design of various optoelectronic devices opened by the use of polarization doping in III‐nitride heterostructures, including distributed polarization doping (DPD) in graded‐composition alloys. The polarization doping is routinely exploiting in high‐electron mobility transistors for a long time. In contrast, this concept has not yet been applied to light‐emitting diodes (LEDs), laser diodes (LDs), and solar cells (SCs) until recently, in spite of its great potential advantage – capability of producing holes with high concentrations that can never be achieved by conventional impurity doping. Using simulations, we apply the concept of polarization doping to find efficient ways for solution of practically important problems: (i) improvement of p‐doping in deep‐UV LED structures, (ii) development of p‐type Ohmic contact to AlGaN alloys with high aluminum content, and (iii) development of III‐nitride tunnel junctions (TJs) capable of forward bias operation. Band diagram and distribution of carrier concentrations in the prototype of acceptor‐free deep‐UV LED structure considered in the paper.

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“…On one hand, the cross-sectional area for the hole current will be increased, and on the other hand, the overall hole concentration (holes donated by ionized Mg dopants and 3D hole gas) can be significantly enhanced, and hence the device performance can be substantially improved. 10,28 In Fig. 4(a), the PL spectra for both Samples C and D were shown.…”

Section: à3mentioning

confidence: 99%

p-doping-free InGaN/GaN light-emitting diode driven by three-dimensional hole gas

Zhang

Tan

Kyaw

et al. 2013

Applied Physics Letters

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Here, GaN/AlxGa1-xN heterostructures with a graded AlN composition, completely lacking external p-doping, are designed and grown using metal-organic-chemical-vapour deposition (MOCVD) system to realize three-dimensional hole gas (3DHG). The existence of the 3DHG is confirmed by capacitance-voltage measurements. Based on this design, a p-doping-free InGaN/GaN light-emitting diode (LED) driven by the 3DHG is proposed and grown using MOCVD. The electroluminescence, which is attributed to the radiative recombination of injected electrons and holes in InGaN/GaN quantum wells, is observed from the fabricated p-doping-free devices. These results suggest that the 3DHG can be an alternative hole source for InGaN/GaN LEDs besides common Mg dopants.

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Improvement of efficiency of GaN-based polarization-doped light-emitting diodes grown by metalorganic chemical vapor deposition

Cited by 35 publications

References 15 publications

Efficiency enhancement of blue InGaN/GaN light-emitting diodes with an AlGaN-GaN-AlGaN electron blocking layer

Efficiency enhancement of blue InGaN/GaN light-emitting diodes with an AlGaN-GaN-AlGaN electron blocking layer

Polarization doping for III-nitride optoelectronics

p-doping-free InGaN/GaN light-emitting diode driven by three-dimensional hole gas

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