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Enhancement of wall-plug efficiency in vertical InGaN/GaN LEDs by improved current spreading
Jun Ho Son1, Buem Joon Kim, Chul Jong Ryu
1Department of Materials Science and Engineering, Division of Advanced Materials Science, Pohang University of Science and Technology, Pohang, Gyeongbuk 790-874, South Korea.
Abstract:
We present the enhancement of wall-plug efficiency in vertical InGaN/GaN light-emitting diodes (V-LEDs) by improved current spreading with a novel Al2O3 current blocking layer (CBL). The Al2O3 CBL deposited by electron-beam evaporation shows high transmittance and good corrosion resistance to acidic solutions. V-LEDs with an Al2O3 CBL show similar light output power but lower forward voltage as compared to those with a SiO2 CBL deposited by plasma-enhanced chemical vapor deposition. As a result, the wall-plug efficiency of V-LEDs with an Al2O3 CBL at 500 mA was improved by 5% as compared to those with a SiO2 CBL, and by 19% as compared to those without a CBL.
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