Abstract
This article describes the successful fabrication of europium-silicate thin film phosphor and its application to InGaN/GaN white light-emitting diodes (LEDs) in order to improve the photometric properties of the LEDs, including their correlated color temperatures (CCT) and color rendering index (CRI). The europium-silicate compounds are deposited on GaN templates grown on sapphire substrates by RF-sputtering and then annealed at 1000 °C in an N2 ambient to form a thin film phosphor that produces yellow or red emissions. The thin film phosphor is then patterned with stripes to grow a GaN buffer layer by epitaxially laterally overgrown GaN (ELOG) techniques, on which LED structures are grown by metal organic chemical vapor deposition. The ELOG sample shows no pits on the surface, and the full widths at half maximum (FWHMs) of its X-ray rocking curve for the (002) and (102) planes are as low as 249 and 416 arcsec, respectively. The optical spectrum from the embedded thin film phosphor is adjusted to have a maximum intensity at 560600 nm and a FWHM as wide as 90 nm to make up for the low efficiency at these wavelengths of conventional YAG-based yellow phosphor. Finally, we observed a tristimulus coordinate (x, y)=(0.33, 0.39), CCT=5607 K, and CRI=77.6 from the white LEDs with thin film phosphor as compared with (x, y)=(0.30, 0.28), CCT=8467 K, and CRI=66.52 for the white LEDs without thin film phosphor.
| Original language | English |
|---|---|
| Article number | 5518521 |
| Pages (from-to) | 1381-1387 |
| Number of pages | 7 |
| Journal | IEEE Journal of Quantum Electronics |
| Volume | 46 |
| Issue number | 9 |
| DOIs | |
| Publication status | Published - 2010 Aug 6 |
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Keywords
- Color rendering indices (CRI)
- correlated color temperatures (CCT)
- europium-silicate
- thin film phosphors
- white light-emitting diodes (LEDs)
ASJC Scopus subject areas
- Electrical and Electronic Engineering
- Atomic and Molecular Physics, and Optics
- Condensed Matter Physics
Cite this
InGaN/GaN white light-emitting diodes embedded with europium silicate thin film phosphor. / Kim, Eun Hong; Kim, Kyoung Chan; Kim, Dong Ho; Baek, Jong Hyeob; Kim, Tae Geun.
In: IEEE Journal of Quantum Electronics, Vol. 46, No. 9, 5518521, 06.08.2010, p. 1381-1387.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - InGaN/GaN white light-emitting diodes embedded with europium silicate thin film phosphor
AU - Kim, Eun Hong
AU - Kim, Kyoung Chan
AU - Kim, Dong Ho
AU - Baek, Jong Hyeob
AU - Kim, Tae Geun
PY - 2010/8/6
Y1 - 2010/8/6
N2 - This article describes the successful fabrication of europium-silicate thin film phosphor and its application to InGaN/GaN white light-emitting diodes (LEDs) in order to improve the photometric properties of the LEDs, including their correlated color temperatures (CCT) and color rendering index (CRI). The europium-silicate compounds are deposited on GaN templates grown on sapphire substrates by RF-sputtering and then annealed at 1000 °C in an N2 ambient to form a thin film phosphor that produces yellow or red emissions. The thin film phosphor is then patterned with stripes to grow a GaN buffer layer by epitaxially laterally overgrown GaN (ELOG) techniques, on which LED structures are grown by metal organic chemical vapor deposition. The ELOG sample shows no pits on the surface, and the full widths at half maximum (FWHMs) of its X-ray rocking curve for the (002) and (102) planes are as low as 249 and 416 arcsec, respectively. The optical spectrum from the embedded thin film phosphor is adjusted to have a maximum intensity at 560600 nm and a FWHM as wide as 90 nm to make up for the low efficiency at these wavelengths of conventional YAG-based yellow phosphor. Finally, we observed a tristimulus coordinate (x, y)=(0.33, 0.39), CCT=5607 K, and CRI=77.6 from the white LEDs with thin film phosphor as compared with (x, y)=(0.30, 0.28), CCT=8467 K, and CRI=66.52 for the white LEDs without thin film phosphor.
AB - This article describes the successful fabrication of europium-silicate thin film phosphor and its application to InGaN/GaN white light-emitting diodes (LEDs) in order to improve the photometric properties of the LEDs, including their correlated color temperatures (CCT) and color rendering index (CRI). The europium-silicate compounds are deposited on GaN templates grown on sapphire substrates by RF-sputtering and then annealed at 1000 °C in an N2 ambient to form a thin film phosphor that produces yellow or red emissions. The thin film phosphor is then patterned with stripes to grow a GaN buffer layer by epitaxially laterally overgrown GaN (ELOG) techniques, on which LED structures are grown by metal organic chemical vapor deposition. The ELOG sample shows no pits on the surface, and the full widths at half maximum (FWHMs) of its X-ray rocking curve for the (002) and (102) planes are as low as 249 and 416 arcsec, respectively. The optical spectrum from the embedded thin film phosphor is adjusted to have a maximum intensity at 560600 nm and a FWHM as wide as 90 nm to make up for the low efficiency at these wavelengths of conventional YAG-based yellow phosphor. Finally, we observed a tristimulus coordinate (x, y)=(0.33, 0.39), CCT=5607 K, and CRI=77.6 from the white LEDs with thin film phosphor as compared with (x, y)=(0.30, 0.28), CCT=8467 K, and CRI=66.52 for the white LEDs without thin film phosphor.
KW - Color rendering indices (CRI)
KW - correlated color temperatures (CCT)
KW - europium-silicate
KW - thin film phosphors
KW - white light-emitting diodes (LEDs)
UR - http://www.scopus.com/inward/record.url?scp=77955136172&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=77955136172&partnerID=8YFLogxK
U2 - 10.1109/JQE.2010.2049195
DO - 10.1109/JQE.2010.2049195
M3 - Article
AN - SCOPUS:77955136172
VL - 46
SP - 1381
EP - 1387
JO - IEEE Journal of Quantum Electronics
JF - IEEE Journal of Quantum Electronics
SN - 0018-9197
IS - 9
M1 - 5518521
ER -