P-side-up thin-film AlGaInP-based light emitting diodes with direct ohmic contact of an ITO layer with a GaP window layer

Tseng, Mei-Chih; Chen, Chi Lu; Lai, Nan Kai; Chen, Shih I.; Hsu, Tzu Chieh; Peng, Yu Ren; Horng, Ray−Hua

doi:10.1364/oe.22.0a1862

Cited by 22 publications

(10 citation statements)

References 13 publications

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“…This type of LED is called LED-I. Details on the fabrication of p-side up AlGaInP-based thin-film LEDs have been reported 12 . Structural diagram of a p-side up AlGaInP-based LED with HHPS array is shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Therefore, one of the most crucial issues in AlGaInP-based LED research is increasing the number of photons that escape the active region 5 – 9 . Several efficient methods have been proposed and demonstrated to increase light extraction efficiency (LEE), such as the use of simple random surface roughness structures 10 , photonic crystal structures 11 , graded reflective index materials 12 , 13 , and embedded (or self-assembled) nanostructures 14 – 16 . These technologies have been effectively demonstrated to increase LEE.…”

Section: Introductionmentioning

confidence: 99%

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AlGaInP Red LEDs with Hollow Hemispherical Polystyrene Arrays

Cheng

Huang

Chen

et al. 2018

Sci Rep

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A hollow hemispherical polystyrene (HHPS) was fabricated to reduce total internal reflection in AlGaInP-based LEDs. At an injection current of 350 mA, the external quantum efficiencies of LED-I, LED-II, LED-III, and LED-IV are 20.92%, 24.65%, 27.28%, and 33.77% and the wall-plug efficiencies are 17.11%, 20%, 22.5%, and 27.33%, respectively. The enhanced performance is attributed to the light output power enhancement through the surface roughness, microlens-liked PS hemisphere, and scatter-liked HHPS array. In this paper, the rigorous coupled wave analysis (RCWA) numerical method was also conducted to demonstrate the HHPS array effectively enlarge the effective light cone.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

AlGaInP Red LEDs with Hollow Hemispherical Polystyrene Arrays

Cheng

Huang

Chen

et al. 2018

Sci Rep

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“…1(a), the structure consists of a carbon-doped p+-GaP ohmic-contact layer, p-GaP:Mg window layer, p-cladding AlGaInP, GaInP-AlGaInP MQWs, n-cladding AlGaInP, n + -GaAs contact layer, and a GaInP etching stop layer. Detailed of twice wafer-transfer technology procedures have been reported in our previous studies [6]. The front grid metal of Ti/Al/Ti/Au (25/2000/50/100 nm) was deposited on the top of AZO layer and the bottom electrode of Ti/Au (5/100 nm) was deposited on the rear of LED with silicon substrate.…”

Section: Methodsmentioning

confidence: 99%

“…In order to solve the problem, several method has been proposed, such as surface texture [3], photonic crystal [4], changing the chip shape [5], and auxiliary of transparent contact layer (TCL) on the GaP window layer [6]. Recently, the indium tin oxide (ITO) as TCL has exhibited as one of the most promising material for enhancement of light extraction in AlGaInP-base LED due to its excellent conductivity and optical transparency in the range of visible wavelength [7].…”

Section: Introductionmentioning

confidence: 99%

Study of Aluminum-doped zinc oxide current spreading layer on P-side up thin-film AlGaInP-based light-emitting diodes by ALD

et al. 2015

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A twice wafer-transfer technique can be used to fabricate high-brightness p-side-up thin-film AlGaInP-based light-emitting diodes (LEDs) with an aluminum-doped zinc oxide (AZO) thin films transparent conductive layer deposited on a GaP window layer. The GaP window layer consist of the two different doping profile, the carbon doped Gap (GaP:C) window layer of 50 nm is on the top of Mg doped GaP window layer of 8 μm. The GaP:C window layer is used to improved the ohmic contact properties of GaP:C/AZO. The AZO with different cycle ratio of Zn:Al (15:1, 20:1 and 25:1) is deposited on GaP:C window layer as current spreading layer by atomic layer deposition. The AZO layer can be used to improve light extraction, which enhances light output power. The output power of p-side-up thin-film AlGaInP LED with an AZO layer of 20:1 cycle ratio has improved up to 19.2 % at injection current of 350 mA, as compared with that of LED without AZO film. The p-side-up thin-film AlGaInP LED with AZO current spreading layer exhibited excellent performance stability, the emission wavelength shift of p-side-up thin-film AlGaInP LED without and with AZO thin film(Zn:Al=20:1) are 17 nm and 3 nm under the injection current increased from 20 mA to 1000mA, respectively. This stability can be attributed to the following factors: 1) Refractive index matching, performed by introducing AZO thin film between the epoxy and the GaP window layer enhances light extraction; and 2) the favorable thermal dissipation of the silicon substrate reduces thermal degradation.

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“…Concerning the CIC substrate, mechanical strength has been already proposed and fabricated for thin film AlGaInP LED applications in our recent study 8 , 24 . In this study, the thin film AlGaInP epilayer was successfully transferred to a CIC substrate with a 50-μm thickness using wafer bonding and epilayer transferring technologies 3 , 25 , 26 . Thin film AlGaInP LED chips with a composite metal substrate were developed and obtained high-performance LED/CIC chips using the wet etching process.…”

Section: Introductionmentioning

confidence: 99%

Dicing of composite substrate for thin film AlGaInP power LEDs by wet etching

Horng

Sinha

Tarntair

et al. 2021

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In this paper, thin film AlGaInP LED chips with a 50 μm thick composite metal substrate (Copper-Invar-Copper; CIC) were obtained by the wet etching process. The pattern of the substrate was done by the backside of the AlGaInP LED/CIC. There was no delamination or cracking phenomenon of the LED epilayer which often occurs by laser or mechanical dicing. The chip area was 1140 μm × 1140 μm and the channel length was 360 μm. The structure of the CIC substrate was a sandwich structure and consisted of Cu as the top and bottom layers, with a thickness of 10 μm, respectively. The middle layer was Invar with a 30% to 70% ratio of Ni and Fe and a total thickness of 30 μm. The chip pattern was successfully obtained by the wet etching process. Concerning the device performance after etching, high-performance LED/CIC chips were obtained. They had a low leakage current, high output power and a low red shift phenomenon as operated at a high injected current. After the development and fabrication of the copper-based composite substrate for N-side up thin-film AlGaInP LED/CIC chips could be diced by wet etching. The superiority of wet etching process for the AlGaInP LED/CIC chips is over that of chips obtained by mechanical or laser dicing.

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P-side-up thin-film AlGaInP-based light emitting diodes with direct ohmic contact of an ITO layer with a GaP window layer

Cited by 22 publications

References 13 publications

AlGaInP Red LEDs with Hollow Hemispherical Polystyrene Arrays

AlGaInP Red LEDs with Hollow Hemispherical Polystyrene Arrays

Study of Aluminum-doped zinc oxide current spreading layer on P-side up thin-film AlGaInP-based light-emitting diodes by ALD

Dicing of composite substrate for thin film AlGaInP power LEDs by wet etching

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