Less strained and more efficient GaN light-emitting diodes with embedded silica hollow nanospheres.
Light-emitting diodes (LEDs) become an attractive alternative to conventional light sources due to high efficiency and long lifetime. However, different material properties between GaN and sapphire cause several problems such as high defect density in GaN, serious wafer bowing, particularly in large-area wafers, and poor light extraction of GaN-based LEDs. Here, we suggest a new growth strategy for high efficiency LEDs by incorporating silica hollow nanospheres (S-HNS). In this strategy, S-HNSs were introduced as a monolayer on a sapphire substrate and the subsequent growth of GaN by metalorganic chemical vapor deposition results in improved crystal quality due to nano-scale lateral epitaxial overgrowth. Moreover, well-defined voids embedded at the GaN/sapphire interface help scatter lights effectively for improved light extraction, and reduce wafer bowing due to partial alleviation of compressive stress in GaN. The incorporation of S-HNS into LEDs is thus quite advantageous in achieving high efficiency LEDs for solid-state lighting.
Department of Materials Science and Engineering, Seoul National University, Seoul 151-744, Korea.
Jonghak
J
Kim
Heeje
H
Woo
Kisu
K
Joo
Sungwon
S
Tae
Jinsub
J
Park
Daeyoung
D
Moon
Sung Hyun
SH
Park
Junghwan
J
Jang
Yigil
Y
Cho
Jucheol
J
Park
Hwankuk
H
Yuh
Gun-Do
GD
Lee
In-Suk
IS
Choi
Yasushi
Y
Nanishi
Heung Nam
HN
Han
Kookheon
K
Char
Euijoon
E
Yoon