Ultraviolet nitride LED fabrication for high-flux white LED

Venugopalan, H. S.; DiCarlo, Anthony A.; Gao, Xiang; Libon, Sebastien; Shelton, B. S.; Stefanov, Emil; Zhang, Tingting; Eliashevich, I.; Weaver, Stanton; Hsing, Michael; Kolodin, Boris; Soules, Tom; Florescu, D. I.; Guo, Shiping; Pophristić, M.; Peres, B.

doi:10.1117/12.486359

Cited by 15 publications

(3 citation statements)

References 5 publications

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“…6(b) shows the typical reverse characteristics of the VLEDs with both contacts. Venugopalan et al 10 reported that aging of LEDs fabricated with Ag contacts can cause a large increase in the leakage current as a result of lateral migration of Ag. Therefore, the improvement of the reverse characteristics of the ITO/Ni/AgCu/Pt contacts should be associated with the reduction of the Ag migration.…”

Section: Resultsmentioning

confidence: 99%

Enhancement in light extraction efficiency of GaN-based vertical light-emitting diodes by AgCu-based reflectors

2011

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Indium-tin-oxide (ITO)/Ni/AgCu/Pt reflectors for high-performance GaN-based vertical light-emitting diodes (VLEDs) were investigated. The ITO layer was first annealed at 650 °C in air to make an Ohmic contact and then the Ni/AgCu/Pt reflectors were deposited and subsequently annealed at 400 °C in air to improve their reflectance and mechanical adhesion with the ITO layer. It was shown that the reflectance of the ITO/Ni/AgCu/Pt reflectors at 460nm was slightly increased from 82 to 87% after second annealing. Based on the secondary ion mass spectrometry depth profiles, this improvement was attributed to the formation of a transparent Ni-oxide and the existence of Cu atoms near ITO/AgCu/Pt interface regions suppressing the inter and out-diffusion of Ag. The VLEDs fabricated with the ITO/Ni/AgCu/Pt reflectors showed an approximately 4.4% higher output power and much better current-voltage characteristics than those with the Ag-based reflectors.

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Section: Resultsmentioning

confidence: 99%

Enhancement in light extraction efficiency of GaN-based vertical light-emitting diodes by AgCu-based reflectors

2011

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“…7 shows the typical reverse characteristics of the VLEDs with both contacts. Venugopalan et al 16) reported that aging of LEDs fabricated with Ag contacts can cause a large increase in the leakage current as a result of lateral migration of Ag. Therefore, the improvement of the reverse characteristics of the ITO/Ni/AgCu/Pt contacts should be associated with the reduction of the Ag migration.…”

Section: Resultsmentioning

confidence: 99%

Formation of Thermally Stable AgCu-Based Reflectors by a Two Step Alloy Method for Vertical Light-Emitting Diodes

Jeong

Kim²,

Lee³

et al. 2010

Jpn. J. Appl. Phys.

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Two-step alloyed indium–tin-oxide (ITO)/Ni/AgCu/Pt reflectors for high-performance GaN-based vertical light-emitting diodes (VLEDs) were investigated. The ITO layer was first annealed at 650 °C for 1 min in air to make an Ohmic contact and then the Ni/AgCu/Pt reflectors were deposited and subsequently annealed at 400 °C for 1 min in air to improve their reflectance and mechanical adhesion with the ITO layer. It was shown that the reflectance of the ITO/Ni/AgCu/Pt reflectors at 460 nm was slightly increased from 82 to 87% after two-step annealing. Based on the secondary ion mass spectrometry depth profiles, this improvement was attributed to the formation of a transparent Ni-oxide and the existence of Cu atoms near ITO/AgCu/Pt interface regions suppressing the inter and out-diffusion of Ag. The VLEDs fabricated with the ITO/Ni/AgCu/Pt reflectors showed an approximately 4.4% higher output power and much better current–voltage characteristics than those with the Ag-based reflectors.

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“…The reverse leakage current can be attributed to diffusion, recombination, tunnelling, and, when illuminated, the photocurrent in the space-charge region. There have been also some studies on nitride-based LEDs that attributed the leakage current to a high threading defect density of the devices [3, 4], metal migration [5], and surface diffusion [6]. However, in the case of nitride-based LEDs, tunnelling of electrons into the conduction band is the most likely cause of reverse leakage current because the other mechanisms are small in magnitude owing to a wide bandgap of nitride-based LEDs and have rather weak voltage dependence.…”

mentioning

confidence: 99%