led: critical research issues - us department of...
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Future Chips ConstellationRensselaer
CW 2012- 6- 1C. Wetzel
January 30, 2013
Future Chips Constellation, Department of Physics, Applied Physics and Astronomy
Rensselaer Polytechnic Institute, Troy, NY, USA
LED: Critical Research Issues
DOE Solid State Lighting R&D Workshop Long Beach, CA
Christian Wetzel and Theeradetch Detchprohm
Future Chips ConstellationRensselaer
CW 2011-04 18 C.Wetzel
This work is supported by a United States of America DOE/NETL Solid-State Lighting Contract of Directed Research under DE-EE0000627. This work is also supported by the NSF under cooperative agreement EEC-0812056 and by New York State under NYSTAR contract C090145.
Future Chips Constellation Rensselaer
CW 2012-10-14 1951.c C.Wetzel
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Future Chips ConstellationC. Wetzel
Materials Development Needs
Droop Reduction => Higher Efficiency
=> Higher Lumen => Less Cooling
Integration LED + Phosphor => Direct Spectrum LED
Integration LED + Driver + Sensor + Controls => AC LED System
Rensselaer CW 2012-06-09 1138.c
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Future Chips ConstellationC. Wetzel
New Ideas on How to Avoid Droop
New ideas need to be tested
Rensselaer CW 2012-06-09 1138.c
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Future Chips ConstellationC. Wetzel
GaN on Nano-Patterned Sapphire
profound change in defect structure
reference LED LED on nanopatterned substrate
8 -2
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Epitaxy on Large Surface Miscut Built-In Patterning the art of light extraction
Entire LEDs in GaN substrate miscut (deg)fish scale pattern
0.06 GaN 0.70 GaN
Su
bst
rate
Ga
N L
ED
C.J.M. Stark et al. Appl. Phys. Lett. 101, 232106 (2012), dx.doi.org/10.1063/1.4769442
2.24 GaN 0.25 Sapphire
LED surface image
Future Chips ConstellationC. Wetzel Rensselaer
CW 2012-06-09 1138.c
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Future Chips ConstellationC. Wetzel
Droop Reduction
Bulk GaN homoepitaxy
New QWs new profile
new alloy
Semipolar substrate
epitaxy
Nano-patterned Si substrate
new substrates
2.24 GaN
C.J.M. Stark et al. Appl. Phys. Lett. 101, 232106 (2012)
Rensselaer CW 2012-06-09 1138.c
Sapphire
cTD
500 nm
GaN
g=(0002)
stacking faults
Yufeng Li, et al. Appl. Phys. Lett, 98(15), 151102 (2011)
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Future Chips ConstellationC. Wetzel
The Green Gap
after: S. DenBaars, LS-13 Intern. Symp. Science Technology Lighting, June 2012, Troy NY
Y. Li et al Appl. Phys. Lett. 98, 151102 (2011)
RPI
window of opportunity
Rensselaer CW 2012-06-09 1138.c
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Future Chips ConstellationC.Wetzel
Composite White Light Emitting Diode
blue plus phosphor
rel.
Inte
nsity
blue LED
solar spectrum
p031407a.o
p020309a.c
T = 6500 K
eye stimulus functions
400 500 600 700 Wavelength (nm)
blue green red
11
00
0
10k
6k
4k
3k 2k
1k
1931 Chromaticity Diagram400 500 600 700 Wavelength (nm)
Rensselaer CW 2012-06-09 1138.c
fox consulting ClipArtOf.com
2006 Philips Lumileds Lighting Company. AB08
http:ClipArtOf.com
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Future Chips ConstellationC.Wetzel
Composite White Light Emitting Diode
blue plus phosphor
rel.
Inte
nsity
blue LED
+ phosphor
solar spectrum
p031407a.o
p020309a.c
T = 6500 K
eye stimulus functions
400 500 600 700 Wavelength (nm)
blue green red
11
00
0
10k
6k
4k
3k 2k
1k
1931 Chromaticity Diagram400 500 600 700 Wavelength (nm)
Rensselaer CW 2012-06-09 1138.c
fox consulting ClipArtOf.com
2006 Philips Lumileds Lighting Company. AB08
http:ClipArtOf.com
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Future Chips ConstellationC. Wetzel
Proper Placement of Phosphor Layer
index and thermal matching
Index of PropagationTemperature LED refraction time
n zz + z
_
Phosphor
Useful
flux
sandwiched phosphor too hot of for standard phosphor
Rensselaer CW 2012-06-09 1138.c
schematic
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Future Chips ConstellationC.Wetzel
Proper Placement of Phosphor Layer
index and thermal matching
Index of PropagationTemperature LED refraction time
z z n zz+
_
Phosphor
Useful flux
Rensselaer CW 2012-06-09 1138.c
remote phosphor high light coupling losses
schematic
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Future Chips ConstellationC.Wetzel
Proper Placement of Phosphor Layer
index and thermal matching
Index of PropagationTemperature LED refraction time
z z n zz+
_ Phosphor
Useful
flux
phosphor in source highest possible flux need epi compatible
Rensselaer CW 2012-06-09 1138.c
schematic
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Composite White Light Emitting Diode
RGB LED
10k
6k
4k
3k 2k
1k
1931 Chromaticity Diagram0
eye stimulus functions
blue green red
0
1
rel.
Inte
nsity
solar spectrum
0
1
400 500 600 700 Wavelength (nm)
T = 6500 K
human eye
visible
schematic
CW
_2011-0
8-1
9_1938.c
400 500 600 700 Wavelength (nm)
emc.cmich.edu/sunsafety ClipArtOf.com Rensselaer Future Chips ConstellationC.Wetzel Rensselaer Future Chips ConstellationC.Wetzel
CW 2012-06-09 1138.c
http:ClipArtOf.com
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Composite White Light Emitting Diode
RGBY LED
400 500 600 700 0
eye stimulus functions
blue green red
1931 Chromaticity Diagram
0
1
rel.
Inte
nsity
solar spectrum
0
1
400 500 600 700 Wavelength (nm)
T = 6500 K
human eye
visible
schematic
CW
_2011-0
8-1
9_1938.c
Wavelength (nm)
emc.cmich.edu/sunsafety ClipArtOf.com Rensselaer Future Chips ConstellationC.Wetzel Rensselaer Future Chips ConstellationC.Wetzel
CW 2012-06-09 1138.c
http:ClipArtOf.com
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Future Chips ConstellationC.Wetzel
Direct Spectrum LED
keep it semiconductor
Green, Yellow Red rare earth free phosphor free index matched InGaN or some new alloy
Individual RGBY semipolar bulk GaN-based
Multicolored RGBY microstructured nanostructured
0
1
rel.
Inte
nsity
solar spectrum
0
1
400 500 600 700 Wavelength (nm)
T = 6500 K
human eye
visible
schematic
CW
_2
011
-08
-19
_1
93
8 c
Rensselaer CW 2012-06-09 1138.c
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Future Chips ConstellationC. Wetzel
Luxeon White LED
epi - chip - lamp
Chip
Epi
Flip chip - style
Lamp
Rensselaer CW 2012-06-09 1138.c
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Future Chips ConstellationC. Wetzel
Periphery
old world technology
www.biztrademarket.com
+ Driver + Cooling
... an awkward BOM (Bill of Materials)
Rensselaer CW 2012-06-09 1138.c
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CREE
Future Chips ConstellationC. Wetzel
Standard Bulb Replacement fits the socket
Soraa
MR-16 PAR-38 A19
sipilPh
Rensselaer CW 2012-06-09 1138.c
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Future Chips ConstellationC. Wetzel
Nostalgia or Progress to Quality of Life?
as seen where people are
boutique or
trendsetter?
Published: Friday, October 26, 2012
The Charles F. Lucas Confectionery & Wine Bar Troy, NY
Rensselaer CW 2012-06-09 1138.c
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Future Chips ConstellationC. Wetzel
Complete Integration on the Materials Level
the better way to go
Integrated driver + sensor
logic _
_S G D +GaN-based Heterostructure
any substrate
LED Transistor Capacitor
Rensselaer CW 2012-06-09 1138.c
schematic
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Future Chips ConstellationC. Wetzel
High Voltage LED, AC LED
daisy chaining
+
_
+
_
+
_
Why not 60 V?LED LED LED110 V?
240 V?
Rensselaer CW 2012-06-09 1138.c
schematic
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Future Chips ConstellationC. Wetzel
High Voltage LED, AC LED
daisy chaining
Tunnel Tunnel
Junction Junction
+
_
Why not 60 V?LED LED LED110 V?
240 V?
Rensselaer CW 2012-06-09 1138.c
schematic
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Future Chips ConstellationC. Wetzel
High Voltage LED, AC LED
daisy chaining
Reversible Reversible Tunnel Tunnel
Junction Junction
~ ~
Why not 60 V?LED LED LED110 V?
240 V?
Rensselaer CW 2012-06-09 1138.c
schematic
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Future Chips ConstellationC. Wetzel
The New Bulb
the way you gonna know it
LED LED LED
Rensselaer CW 2012-06-09 1138.c
schematic
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Future Chips ConstellationC. Wetzel
AC LED System
Convergence Integration
LED + FET, Monolithic
FET + Capacitor Epitaxial
Sensors + Logic Same Materials +
_
CW
_2 0
12
-10
-14 _
04
22
.c
Rensselaer CW 2012-06-09 1138.c
_+ S G DMOVPE GaN-based
Heterostructure
Defect reduced HVPE template
LED Capacitor Transistor
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Future Chips ConstellationC.Wetzel
Materials Development Needs
Droop Reduction => Higher Efficiency
=> Higher Lumen Yufeng Li, et al.
Appl. Phys. Lett, 98(15), 151102 (2011)=> Less Cooling
Integration LED + Phosphor => Direct Spectrum LED
Integration LED + Driver + Sensor + Controls
+
_ _=> AC LED System + S G D
Sapphire
c
voids
TD
500 nm
GaN
g (0002)
stacking faults
0
1
rel
nten
sity
solar spectrum
0
1
400 500 600 700 Wavelength (nm)
T = 6500 K
human eye
visible
schematic
CW
_2
011
-08
-19
_1
93
8.c
Rensselaer CW 2012-06-09 1138.c
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10th International Conference on Nitride Semiconductors
Christian Wetzel Jaime A. Freitas, Jr.
Washington DC, USA Asif Khan Honorary ChairAugust 25-30, 2013
www.icns10.org expected attendance: >1000
- Bulk Crystal Growth - Epitaxial Growth - Optical and Electronic Properties - Processing and Fabrication - Defect Characterization and Engineering - Structural Analysis - Theory and Simulation - Nanostructures - Light Emitting Devices - Electron Transport Devices - Photovoltaics and Energy Harvesting - New Materials and New Device Concepts
http:www.icns10.org
LED: Critical Research IssuesMaterials Development NeedsNew Ideas on How to Avoid DroopDroop ReductionThe Green GapComposite White Light Emitting DiodeProper Placement of Phosphor LayerComposite White Light Emitting DiodeDirect Spectrum LEDLuxeon White LEDPeripheryStandard Bulb ReplacementNostalgia or Progress to Quality of Life?Complete Integration on the Materials LevelHigh Voltage LED, AC LEDThe New BulbAC LED System