Improved Light Extraction Efficiency of GaN Based Blue Light Emitting Diode Using Nano-Scaled Patterned Sapphire Substrate

2019 ◽  
Vol 14 (12) ◽  
pp. 1655-1659
Author(s):  
Young Hoon Sung ◽  
Jaemin Park ◽  
Eun-Seo Choi ◽  
Hee Chul Lee ◽  
Heon Lee
Keyword(s):  
Sapphire Substrate ◽  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Light Extraction Efficiency ◽  
Photoluminescence Intensity ◽  
Patterned Sapphire Substrate ◽  
Light Emitting ◽  
Sapphire Wafer ◽  
Conical Shape ◽  
Luminescence Efficiency

In this study, two different conical-shape nano-patterns were fabricated on the 2-inch diameter sapphire wafer in order to improve the efficiency of light-emitting diodes. The conical-shape nano-patterns were fabricated on the sapphire wafer using a nanoimprint technique and dry etching method. A blue LED structure was grown on the nanoscale-patterned sapphire substrates. The photoluminescence and electroluminescence were measured to confirm the effectiveness of the nano-scale patterns. An improvement in the luminescence efficiency was observed in case that nano-patterned sapphire substrate was used; a 1.44 times-higher photoluminescence intensity and a 1.5 times-higher electroluminescence intensity were observed, compared to those of the light-emitting diodes structure grown on a conventional flat sapphire wafer.

Improved Light Extraction Efficiency of Light-Emitting Diode Grown on Nanoscale-Silicon-Dioxide-Patterned Sapphire Substrate

2020 ◽  
Vol 12 (5) ◽  
pp. 647-651 ◽  
Author(s):  
Young Hoon Sung ◽  
Jaemin Park ◽  
Eun-Seo Choi ◽  
Hee Chul Lee ◽  
Heon Lee
Keyword(s):  
Silicon Dioxide ◽  
Sapphire Substrate ◽  
Extraction Efficiency ◽  
Light Emitting Diode ◽  
Light Extraction ◽  
Light Extraction Efficiency ◽  
Patterned Sapphire Substrate ◽  
Light Emitting ◽  
Sapphire Wafer ◽  
Luminescence Efficiency

A conical-shaped Si dioxide nano-pattern was employed to sapphire substrate in order to improve the light extraction efficiency of light-emitting diodes. The conical-shaped Si dioxide nano-patterns were fabricated on a 2-inch sapphire wafer using direct imprinting of hydrogen silsesquioxane material. A blue-LED structure was grown on conical-shaped silicon-dioxide nano-patterned sapphire substrates. Photoluminescence and electroluminescence measurements were used to confirm the effectiveness of the nanoscale Si oxide patterned sapphire. An improvement in the luminescence efficiency was observed when nanoscale Si oxide patterned sapphire substrate was used. 1.5 times higher PL intensity and 1.6 times higher EL intensity were observed for GaN LED structure grown on nanoscale Si oxide patterned sapphire, compared to LED structure grown on conventional flat sapphire wafer.

scholarly journals Effect of Top-Region Area of Flat-Top Pyramid Patterned Sapphire Substrate on the Optoelectronic Performance of GaN-Based Light-Emitting Diodes

2016 ◽  
Vol 2016 ◽  
pp. 1-8
Author(s):  
Hsu-Hung Hsueh ◽  
Sin-Liang Ou ◽  
Yu-Che Peng ◽  
Chiao-Yang Cheng ◽  
Dong-Sing Wuu ◽  
...  
Keyword(s):  
Sapphire Substrate ◽  
Light Emitting Diodes ◽  
Light Extraction ◽  
Light Extraction Efficiency ◽  
X Ray Diffraction ◽  
Patterned Sapphire Substrate ◽  
Light Emitting ◽  
Sapphire Substrates ◽  
Patterned Sapphire Substrates

The flat-top pyramid patterned sapphire substrates (FTP-PSSs) have been prepared for the growth of GaN epilayers and the fabrication of lateral-type light-emitting diodes (LEDs) with an emission wavelength of approximately 470 nm. Three kinds of FTP-PSSs, which were denoted as FTP-PSS-A, FTP-PSS-B, and FTP-PSS-C, respectively, were formed through the sequential wet etching processes. The diameters of circle areas on the top regions of these three FTP-PSSs were 1, 2, and 3 μm, respectively. Based on the X-ray diffraction results, the full-width at half-maximum values of rocking curves at (002) plane for the GaN epilayers grown on conventional sapphire substrate (CSS), FTP-PSS-A, FTP-PSS-B, and FTP-PSS-C were 412, 238, 346, and 357 arcsec, while these values at (102) plane were 593, 327, 352, and 372 arcsec, respectively. The SpeCLED-Ratro simulation results reveal that the LED prepared on FTP-PSS-A has the highest light extraction efficiency than that of the other devices. At an injection current of 350 mA, the output powers of LEDs fabricated on CSS, FTP-PSS-A, FTP-PSS-B, and FTP-PSS-C were 157, 254, 241, and 233 mW, respectively. The results indicate that both the crystal quality of GaN epilayer and the light extraction of LED can be improved via the use of FTP-PSS, especially for the FTP-PSS-A.

scholarly journals The Optical Properties of InGaN/GaN Nanorods Fabricated on (-201) β-Ga2O3 Substrate for Vertical Light Emitting Diodes

Photonics ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 42
Author(s):  
Jie Zhao ◽  
Weijiang Li ◽  
Lulu Wang ◽  
Xuecheng Wei ◽  
Junxi Wang ◽  
...  
Keyword(s):  
Stark Effect ◽  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Strain Relaxation ◽  
Blue Shift ◽  
Peak Position ◽  
Excitation Power ◽  
Light Extraction Efficiency ◽  
Excitation Power Density ◽  
Light Emitting

We fabricated InGaN/GaN nanorod light emitting diode (LED) on (-201) β-Ga2O3 substrate via the SiO2 nanosphere lithography and dry-etching techniques. The InGaN/GaN nanorod LED grown on β-Ga2O3 can effectively suppress quantum confined Stark effect (QCSE) compared to planar LED on account of the strain relaxation. With the enhancement of excitation power density, the photoluminescence (PL) peak shows a large blue-shift for the planar LED, while for the nanorod LED, the peak position shift is small. Furthermore, the simulations also show that the light extraction efficiency (LEE) of the nanorod LED is approximately seven times as high as that of the planar LED. Obviously, the InGaN/GaN/β-Ga2O3 nanorod LED is conducive to improving the optical performance relative to planar LED, and the present work may lay the groundwork for future development of the GaN-based vertical light emitting diodes (VLEDs) on β-Ga2O3 substrate.

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