TITLE:
Enhancement of InGaN-Based Light Emitting Diodes Performance Grown on Cone-Shaped Pattern Sapphire Substrates
AUTHORS:
Huanyou Wang, Yalan Li, Penghua Zhang
KEYWORDS:
Metal-Organic Chemical Vapor Deposition (MOCVD), Patterned Sapphire Substrate, Optical Emission, Lateral Growth
JOURNAL NAME:
Journal of Materials Science and Chemical Engineering,
Vol.2 No.7,
July
8,
2014
ABSTRACT: To enhance light
extraction effciency, high-quality InGaN-based light emitting diodes (LED) was
grown on cone-shaped patterned sapphire (CPSS) by using metal organic chemical
vapor deposition (MOCVD). From the transmission electron microscopy (TEM)
observation, the CPSS was confirmed to be an efficient way to reduce the
threading dislocation density in the GaN epilayer. A sharp and high intensity
Photoluminescence (PL) for LED on CPSS at 457 nm compared to LED on unpattern
planar sapphire substrates (USS) indicates that the crystalline quality was
improved significantly and the internal reflection on the cones of the
substrate was enhanced. The output power of the LED on CPSS is higher than that
of LED on USS. The achieved improvement of the output power is not only due to
the improvement of the internal quantum efficiency upon decreasing the
dislocation density, but also due to the enhancement of the extraction
efficiency using the CPSS.