Analysis of the Thickness Effect of Undoped Electron-Blocking Layer in Ultraviolet LEDs

Lin, Wenyu; Wang, Tzu-Yu; Liang, Jiahao; Ou, Sin-Liang; Wuu, Dong−Sing

doi:10.1109/ted.2014.2356557

Cited by 10 publications

(3 citation statements)

References 13 publications

(11 reference statements)

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“…However, low intensity luminescence has become the main limitation of the lighting source in which it is caused by the low radiative recombination in the epitaxial chip. There are few factors that ignite the low radiative recombination such as electron overflow [12][13][14], low hole injection into the active region [15,16] and parasitic carrier reservoir due to the high polarization effects [9,[17][18][19]. Numerous research has been performed to overcome the electron overflow and low hole injection such as incorporating the electron blocking layer (EBL) between the active region and the hole injection layer [3,12,18,20,21].…”

Section: Introductionmentioning

confidence: 99%

“…There are few factors that ignite the low radiative recombination such as electron overflow [12][13][14], low hole injection into the active region [15,16] and parasitic carrier reservoir due to the high polarization effects [9,[17][18][19]. Numerous research has been performed to overcome the electron overflow and low hole injection such as incorporating the electron blocking layer (EBL) between the active region and the hole injection layer [3,12,18,20,21]. The presence of EBL in the epitaxial chip intensifies the polarization effects involving the spontaneous and piezoelectric polarizations [17,22].…”

Section: Introductionmentioning

confidence: 99%

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Low parasitic carrier reservoir of AlGaN-based DUV-LED via controlled-polarization step-graded superlattice electron blocking layer for high luminescence lighting

Hairol Aman,

Ahmad Noorden,

Daud

et al. 2024

Phys. Scr.

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Achieving high luminescence intensity of deep-ultraviolet light-emitting diode (DUV-LED) is generally performed through the implementation of electron blocking layer (EBL) on the chip’s epilayers. However, the issue of parasitic carrier reservoir that originated from the uncontrolled piezoelectric field polarization has restricted the performance of DUV-LED by reducing the radiative recombination in the active region. This work reports on the numerical computation analysis of the DUV-LED with different types of EBL designs which are reference EBL, conventional superlattice EBL and step-graded superlattice EBL. The analysis of the DUV-LED focuses on the band diagram, carrier concentration at the EBL interfaces, current density of the carrier in the active region, radiative recombination rates, and luminescence spectrum. Remarkably, it is found that the DUV-LED step-graded superlattice EBL provides the polarization-controlled band diagram and emits 272 nm UVC-wavelength in which it is superior in performance compared to the other structures, specifically in terms of its radiated intensity. The parasitic electron and hole reservoir have been reduced by 30% and 60%, respectively. The luminescence intensity was also enhanced by 11% compared with the reference EBL and the IQE obtained by the DUV-LED with step-graded superlattice EBL is 50.12%.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Low parasitic carrier reservoir of AlGaN-based DUV-LED via controlled-polarization step-graded superlattice electron blocking layer for high luminescence lighting

Hairol Aman,

Ahmad Noorden,

Daud

et al. 2024

Phys. Scr.

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“…Moreover, the diffusion of Mg atoms from the p-region to the active region is more severe in high-Al composition structures [10]. The induced Mg-related defects in multiple QWs (MQWs) will form nonradiative recombination centers, which is detrimental to the low internal quantum efficiency (IQE) [11]. Besides, the Mginduced defect will scatter electrons, leading to a low electron mobility [12].…”

Section: Introductionmentioning

confidence: 99%

BAlN for III-nitride UV light-emitting diodes: undoped electron blocking layer

Gu¹,

Lu²,

Lin³

et al. 2021

J. Phys. D: Appl. Phys.

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The undoped BAlN electron-blocking layer (EBL) is investigated to replace the conventional AlGaN EBL in light-emitting diodes (LEDs). Numerical studies of the impact of variously doped EBLs on the output characteristics of LEDs demonstrate that the LED performance shows heavy dependence on the p-doping level in the case of the AlGaN EBL, while it shows less dependence on the p-doping level for the BAlN EBL. As a result, we propose an undoped BAlN EBL for LEDs to avoid the p-doping issues, which a major technical challenge in the AlGaN EBL. Without doping, the proposed BAlN EBL structure still possesses a superior capacity in blocking electrons and improving hole injection compared with the AlGaN EBL having high doping. Compared with the Al0.3Ga0.7N EBL with a doping concentration of 1 × 1020 cm−3, the undoped BAlN EBL LED still shows lower droop (only 5%), compatible internal quantum efficiency (2% enhancement), and optical output power (6% enhancement). This study provides a feasible route to addressing electron leakage and insufficient hole injection issues when designing ultraviolet LED structures.

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ITO/nano‐Ag plasmonic window applied for efficiency improvement of near‐ultraviolet light emitting diodes

Tien

Zhang

Chung

et al. 2016

Physica Status Solidi (a)

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In this study, to enhance the emission efficiency of GaN‐based near‐ultraviolet light‐emitting diodes (NUV‐LEDs), the ITO/nano‐Ag plasmonic window which possessed localized surface plasmon (LSP) coupling effect was prepared on the roughened p‐GaN layer. The LSP coupling was generated on the grating nanostructure, resulting from the spin‐coated Ag nanoparticles onto the p‐GaN layer. To obtain an obvious LSP coupling, the Ag nanoparticles should be distributed on the p‐GaN uniformly. Thus, the p‐GaN layer was treated via the Ar‐plasma treatment, and it confirmed an uniform distribution of Ag nanoparticles can be prepared on the p‐GaN. The light output power (@350 mA) of the surface‐plasmon‐enhanced NUV‐LED (SPE‐NUV‐LED) with the Ar‐plasma treated p‐GaN possessed 73.7% improvement compared with that of the conventional NUV‐LED (C‐NUV‐LED). This improvement can be attributed to the formation of LSP effect in Ag nanoparticles embedded in the roughened p‐GaN, resulting from the coupling between the excitons in MQWs and the LSP in Ag nanoparticles.

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Analysis of the Thickness Effect of Undoped Electron-Blocking Layer in Ultraviolet LEDs

Cited by 10 publications

References 13 publications

Low parasitic carrier reservoir of AlGaN-based DUV-LED via controlled-polarization step-graded superlattice electron blocking layer for high luminescence lighting

Low parasitic carrier reservoir of AlGaN-based DUV-LED via controlled-polarization step-graded superlattice electron blocking layer for high luminescence lighting

BAlN for III-nitride UV light-emitting diodes: undoped electron blocking layer

ITO/nano‐Ag plasmonic window applied for efficiency improvement of near‐ultraviolet light emitting diodes

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