Forming the graded-refractive-index antireflection layers on light-emitting diodes to enhance the light extraction

Joong Yeon Cho, Kyeong Jae Byeon, Heon Lee

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25 Citations (Scopus)


Distributed antireflection (AR) layers with different composition ratios of ITO and SiO2 formed on an ITO electrode of GaN-based LEDs provide substantial enhancement in light-extraction efficiency. By using the coradio frequency magnetron sputtering deposition, four 50nm thick AR layers with graduated refractive indices were fabricated. The effect of the AR layers on enhancing the efficiency of the LED device was analyzed by electroluminescence (EL) and I-V measurements. As a result, the EL intensity of the LED device grown on the patterned sapphire substrate with AR layers was increased by up to 13% compared to the conventional patterned sapphire substrate-applied LED device without AR layers at a drive current of 20mA. The AR layers on top of the LED device gradually changed the refractive indices between ITO (n = 2:1) and air (n = 1:0), which minimized the total internal reflection of generated light. And no degradation in the electrical characteristic of the LEDs was observed according to the I-V measurements.

Original languageEnglish
Pages (from-to)3203-3205
Number of pages3
JournalOptics Letters
Issue number16
Publication statusPublished - 2011 Aug 15


ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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