InGaN MQW LED structures using AlN/GaN DBR and Ag-based p-contact

ABSTRACTResonant cavity light emitting diode (RCLED) structure was grown using digital AlGaN/GaN Distributed Bragg Reflector (DBR) and Ag-based p-contact. A five period of InGaN/GaN multi-quantum well (MQW) layers are placed between these two high reflectance mirrors. Digital AlGaN/GaN DBR have a maximum reflectivity of about 60 % at 445 nm and 90 % at 439 nm for 6 period and 12 period, respectively. Ag-based p-contact exhibits an average reflectance of around 85-90 % for a wavelength of 400-600 nm. The light output intensity of the RCLEDs with 12 period digital AlGaN/GaN DBR is higher by a factor of 3 as compared to that of the similar structure without digital AlGaN/GaN DBR at an injection current of 50 mA.

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GaN-based resonant-cavity light-emitting diode with an embedded porous-AlGaN distributed Bragg reflector (Conference Presentation)

Light-Emitting Devices, Materials, and Applications ◽

10.1117/12.2511394 ◽

2019 ◽

Cited By ~ 1

Author(s):

Chia-Feng Lin ◽

Jung Han

Keyword(s):

Light Emitting Diode ◽

Resonant Cavity ◽

Bragg Reflector ◽

Distributed Bragg Reflector ◽

Light Emitting

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Light-Output Enhancement of GaN-Based Light-Emitting Diodes with Three-Dimensional Backside Reflectors Patterned by Microscale Cone Array

The Scientific World JOURNAL ◽

10.1155/2014/837586 ◽

2014 ◽

Vol 2014 ◽

pp. 1-6

Author(s):

Huamao Huang ◽

Jinyong Hu ◽

Hong Wang

Keyword(s):

Light Emitting Diode ◽

Three Dimensional ◽

Light Output ◽

Bragg Reflector ◽

Light Extraction Efficiency ◽

Distributed Bragg Reflector ◽

Etching Technique ◽

Light Emitting ◽

Triangle Lattice ◽

Wall Plug Efficiency

Three-dimensional (3D) backside reflector, compared with flat reflectors, can improve the probability of finding the escape cone for reflecting lights and thus enhance the light-extraction efficiency (LEE) for GaN-based light-emitting diode (LED) chips. A triangle-lattice of microscale SiO2cone array followed by a 16-pair Ti3O5/SiO2distributed Bragg reflector (16-DBR) was proposed to be attached on the backside of sapphire substrate, and the light-output enhancement was demonstrated by numerical simulation and experiments. The LED chips with flat reflectors or 3D reflectors were simulated using Monte Carlo ray tracing method. It is shown that the LEE increases as the reflectivity of backside reflector increases, and the light-output can be significantly improved by 3D reflectors compared to flat counterparts. It can also be observed that the LEE decreases as the refractive index of the cone material increases. The 3D 16-DBR patterned by microscale SiO2cone array benefits large enhancement of LEE. This microscale pattern was prepared by standard photolithography and wet-etching technique. Measurement results show that the 3D 16-DBR can provide 12.1% enhancement of wall-plug efficiency, which is consistent with the simulated value of 11.73% for the enhancement of LEE.

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InGaN Resonant-Cavity Light-Emitting Diodes with Porous and Dielectric Reflectors

Applied Sciences ◽

10.3390/app11010008 ◽

2020 ◽

Vol 11 (1) ◽

pp. 8

Author(s):

Cheng-Jie Wang ◽

Ying Ke ◽

Guo-Yi Shiu ◽

Yi-Yun Chen ◽

Yung-Sen Lin ◽

...

Keyword(s):

Active Layer ◽

Optical Pumping ◽

Light Emitting Diode ◽

Resonant Cavity ◽

Bragg Reflector ◽

Distributed Bragg Reflector ◽

Central Wavelength ◽

Light Emitting ◽

Pl Spectra ◽

Cavity Structure

InGaN based resonant-cavity light-emitting diode (RC-LED) structures with an embedded porous-GaN/n-GaN distributed Bragg reflector (DBR) and a top dielectric Ta2O5/SiO2 DBR were demonstrated. GaN:Si epitaxial layers with high Si-doping concentration (n+-GaN:Si) in the 20-period n+-GaN/n-GaN stacked structure were transformed into a porous-GaN/n-GaN DBR structure through the doping-selective electrochemical wet etching process. The central wavelength and reflectivity were measured to be 434.3 nm and 98.5% for the porous DBR and to be 421.3 nm and 98.1% for the dielectric DBR. The effective 1λ cavity length at 432nm in the InGaN resonant-cavity consisted of a 30 nm-thick Ta2O5 spacer and a 148 nm-thick InGaN active layer that was analyzed from the angle-resolved photoluminescence (PL) spectra. In the optical pumping PL spectra, non-linear emission intensity and linewidths reducing effect, from 6.5 nm to 0.7 nm, were observed by varying the laser pumping power. Directional emission pattern and narrow linewidth were observed in the InGaN active layer with bottom porous DBR, top dielectric DBR, and the optimum spacer layer to match the short cavity structure.

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