Nanopatterned aluminum nitride template for high efficiency light-emitting diodes.
Nanopatterned aluminum nitride (NP-AlN) templates were used to enhance the light extraction efficiency of the light-emitting diodes (LEDs). Here, the NP-AlN interlayer between the sapphire substrate and GaN-based LED was used as an effective light outcoupling layer at the direction of bottom side and as a buffer layer for growth of GaN LEDs. The cross-sectional transmission electron microscopy (TEM) analysis showed that the formation of stacking faults and voids could help reduce the threading dislocations. Micro Raman spectra also revealed that the GaN-based epilayer grown on the NP-AlN template had smaller residual stress than that grown on a planar sapphire substrate. The normalized electroluminescence (EL) spectra at the top and bottom sides of device revealed that the enhancement of the bottom side emission of the LED with the NP-AlN interlayer was more notable than a planar sapphire substrate due to the graded-refractive-index (GRIN) effect of the NP-AlN.
Kim
Sang-Mook
SM
Department of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), 1 Oryongdong, Buk-gu, Gwangju 500-712, Republic of Korea.
Park
Tae-Young
TY
Park
Seong-Ju
SJ
Lee
Seung-Jae
SJ
Baek
Jong Hyeob
JH
Park
Yun Chang
YC
Jung
Gun Young
GY