Enhanced light extraction from GaN-based green light-emitting diode with photonic crystal

Abstract

This letter reports the properties of GaN-based green light-emitting diodes ͑LEDs͒ having a p-GaN photonic crystal layer with a photonic bandgap ͑PCWG͒ and without a photonic bandgap ͑PCOG͒. With decreasing the photoluminescence ͑PL͒ detection angle from 140°to 60°, the enhancement of PL intensity of LED with PCWG was largely increased from 9 to 25 times, compared to that of LEDs without a patterned structure, while the PL intensity of LED with PCOG was increased from 4.6 to 5.6 times. The electroluminescence output power of green LEDs with a PCWG was enhanced about two times compared to LEDs with a PCOG. These results suggest that the light extraction of green LEDs can be greatly increased by using PCWG instead of PCOG.

Fabrication of moth-eye structure on p-GaN layer of GaN-based LEDs for improvement of light extraction

“…To solve this problem, there have been many studies on texturing methods, such as photonic crystals [2][3][4], roughening surface [5][6][7], and patterned sapphire substrate (PSS) [8][9][10]. The present study considered the insertion of a moth-eye structure into the InGaNbased LEDs to improve the light extraction efficiency.…”

Recent progress in direct patterning technologies based on nano-imprint lithography

“…Moreover, a flexible substrate and a curved substrate can be patterned by NIL process [128][129][130][131][132][133]. These application fields include organic and inorganic thin film transistors (TFTs) [134][135][136][137][138][139], optical elements and film for various displays [140][141][142], light-emitting devices including LEDs and OLEDs [143][144][145][146][147][148][149][150][151][152], patterned magnetic media [153,154], next-generation random access memory (RAM) devices including resistive RAM and phasechange RAM [155][156][157][158][159][160][161][162][163], and organic and thin film solar cells [164][165][166][167][168]. Various types of nano-and microstructures including one-, two-and three-dimensional structures have been fabricated by NIL and have been applied to diverse devices to enhance the overall performance.…”

Enhanced performance of photonic crystal GaN light-emitting diodes with graphene transparent electrodes

“…They have been widely used in various applications, such as full-color displays, general lighting, etc. [1][2][3]. However, the low light extraction efficiency (η extr ) is a primary obstacle to the realization of higher brightness GaN LED [4][5][6].…”