Simultaneous enhancement of electron overflow reduction and hole injection promotion by tailoring the last quantum barrier in InGaN/GaN light-emitting diodes

Kyaw, Zabu; Zhang, Zihui; Liu, Wei; Tan, Swee Tiam; Ju, Zhen Gang; Zhang, Xue Liang; Ji, Yun; Hasanov, Namig; Zhu, Binbin; Lu, Shunpeng; Zhang, Yiping; Teng, Jinghua; Sun, Xiao Wei; Demir, Hilmi Volkan

doi:10.1063/1.4873395

Cited by 16 publications

(8 citation statements)

References 28 publications

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“…Such different band bending details have been well calculated and can be found in Ref. , and they are now presented in Fig. (a) and (b).…”

Section: Approaches For Improving the Internal Quantum Efficiencysupporting

confidence: 76%

“…However, this structure induces the post‐bonding difficulties thus making it less reliable in reality. Some groups suggest inserting a p‐InGaN before growing the p‐AlGaN EBL to reduce the electron leakage , but the origin on the reduced electron leakage is unclear till now. This can nevertheless be well explained by the polarization inversion effect.…”

Section: Approaches For Improving the Internal Quantum Efficiencymentioning

confidence: 99%

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On the internal quantum efficiency for InGaN/GaN light-emitting diodes grown on insulating substrates

Zhang

et al. 2016

Phys. Status Solidi A

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The internal quantum efficiency (IQE) for InGaN/GaN light‐emitting diodes (LEDs) grown on [0001] sapphire substrates is strongly affected by various factors including polarization effect in the InGaN/GaN multiple quantum wells (MQWs), insufficient electron and hole injections, low p‐type GaN doping efficiency, carrier loss due to the Auger recombination, and current crowding effect especially for the hole current in the p‐GaN region. In this work, the remedies taken by the scientific community to enhance the IQE are reviewed, compared and summarized. Meanwhile, this review also discusses alternative ways including polarization self‐screening effect, polarization cooling, hole accelerator, and hole modulator. The structural solutions we propose in this work can better improve the device performance without increasing the processing difficulty significantly, and their effectiveness in improving the IQE is further supported by the numerical and experimental studies. For example, on the contrary to common belief, the polarizations in the [0001] oriented InGaN/GaN LEDs can be advantageously used to improve the device performance based on our designs.

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“…Such different band bending details have been well calculated and can be found in Ref. , and they are now presented in Fig. (a) and (b).…”

Section: Approaches For Improving the Internal Quantum Efficiencysupporting

confidence: 76%

Section: Approaches For Improving the Internal Quantum Efficiencymentioning

confidence: 99%

On the internal quantum efficiency for InGaN/GaN light-emitting diodes grown on insulating substrates

Zhang

et al. 2016

Phys. Status Solidi A

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“…[16][17][18][19] The significance of using the GaN/InGaN structure as the last quantum barrier to enhance the hole injection has also been presented by several groups. [20][21][22][23][24] Another strategy to improve the hole injection is to increase the hole concentration in the p-GaN layer. The ionization ratio of the Mg doped GaN layer is as low as 1% even after rapid thermal annealing.…”

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confidence: 99%

On the hole accelerator for III-nitride light-emitting diodes

Zhang

et al. 2016

Applied Physics Letters

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In this work, we systematically conduct parametric studies revealing the sensitivity of the hole injection on the hole accelerator (a hole accelerator is made of the polarization mismatched p-electron blocking layer (EBL)/p-GaN/p-AlxGa1−xN heterojunction) with different designs, including the AlN composition in the p-AlxGa1−xN layer, and the thickness for the p-GaN layer and the p-AlxGa1−xN layer. According to our findings, the energy that the holes obtain does not monotonically increase as the AlN incorporation in the p-AlxGa1−xN layer increases. Meanwhile, with p-GaN layer or p-AlxGa1−xN layer thickening, the energy that the holes gain increases and then reaches a saturation level. Thus, the hole injection efficiency and the device efficiency are very sensitive to the p-EBL/p-GaN/p-AlxGa1−xN design, and the hole accelerator can effectively increase the hole injection if properly designed.

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“…Our work is beneficial for the understanding of ELO process and the further development of InGaN/GaN heterostructure based devices. C InGaN/GaN multiple-quantum-well structures have already been extensively used in solid-state light emitting diodes (LEDs) and laser diodes (LDs), [1][2][3][4] where the emission wavelength of such devices can desirably be modulated from near ultraviolet to infrared range by adjusting the indium composition of InGaN. With less effect from polarization field, semi-polar devices are attracting more and more attention for the LEDs and LDs.…”

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confidence: 99%

Influence of dislocations on indium diffusion in semi-polar InGaN/GaN heterostructures

et al. 2015

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The spatial distribution of indium composition in InGaN/GaN heterostructure is a critical topic for modulating the wavelength of light emitting diodes. In this letter, semi-polar InGaN/GaN heterostructure stripes were fabricated on patterned GaN/Sapphire substrates by epitaxial lateral overgrowth (ELO), and the spatial distribution of indium composition in the InGaN layer was characterized by using cathodoluminescence. It is found that the indium composition is mainly controlled by the diffusion behaviors of metal atoms (In and Ga) on the surface. The diffusivity of metal atoms decreases sharply as migrating to the region with a high density of dislocations and other defects, which influences the distribution of indium composition evidently. Our work is beneficial for the understanding of ELO process and the further development of InGaN/GaN heterostructure based devices.

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Simultaneous enhancement of electron overflow reduction and hole injection promotion by tailoring the last quantum barrier in InGaN/GaN light-emitting diodes

Cited by 16 publications

References 28 publications

On the internal quantum efficiency for InGaN/GaN light-emitting diodes grown on insulating substrates

On the internal quantum efficiency for InGaN/GaN light-emitting diodes grown on insulating substrates

On the hole accelerator for III-nitride light-emitting diodes

Influence of dislocations on indium diffusion in semi-polar InGaN/GaN heterostructures

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