Wide Bandgap GaN Epitaxy Energy Efficiency

Wide Bandgap GaN Epitaxy Energy Efficiency

Loading
Loading Social Plug-ins...
Language: English
Save to myLibrary Download PDF
Go to Page # Page of 31

Description: Energy efficiency and green technology with wide band gap GaN-based epitaxy - Phosphor-Free White, Replace rare earth phophors, Avoid Stokes shift losses, Push for wavelength and power, Polarized emitters, Full spectrum emitters, New defect reduction approach.

 
Author: Christian Wetzel (Fellow) | Visits: 2705 | Page Views: 4188
Domain:  Green Tech Category: Lighting Subcategory: HBLED 
Upload Date:
Link Back:
Short URL: https://www.wesrch.com/energy/pdfTR1VRSN9ANISZ
Loading
Loading...



px *        px *

* Default width and height in pixels. Change it to your required dimensions.

 
Contents:
Energy efficiency and green
technology with wide bandgap
GaN-based epitaxy
Christian Wetzel
Future Chips Constellation,
Smart Lighting Engineering Research Center,
Department of Physics, Applied Physics and Astronomy
Rensselaer Polytechnic Institute, Troy, NY, USA

Semicon West
San Francisco, CA
July 10, 2012

C.Wetzel

Rensselaer
CW_2011-04-18_1231.c
CW_2012-06-09_1138.c

Future Chips Constellation

U.S. Primary Energy Consumption
2009: 94.6 Quadrillion BTU

Nuclear

Coal

8.4

20
23
50

Natural Gas

0.7
Wind

Petroleum
Petroleum

30
Hydroelectric
Power

20

1 Quad = 1015 BTU ~ 1018 J
~

Natural Gas

Coal

Nuclear
Electric
Power

10
Wood

0
1850

C.Wetzel

Solar
0.11

35

40

Quadrillion Btu

Geotherm
0.37

Biomass, 3.7
Hydro, 2.7
Other, 1.18

1875
CW_2012-06-09_1138.c

1900

1925

1950

1975

2000

Source:
U.S. Energy Information Administration
Annual Energy Review 2009

Rensselaer
Future Chips Constellation

U.S. Energy Flow – 2009
source to use and waste
Electricity
Generation
38

Solar 0.11
Nuclear 8.4
Hydro 2.7

12

Rejected
Energy
55

26

Wind 0.70
Geotherm 0.37
Natural
Gas 23

40%

Coal 20

of primary
for electricity

Biomass 3.7

31%
conversion

Commercial
8.5

efficiency

Industrial
22

Energy
Services
40

Transportation
27

Petroleum
35

1 Quad = 1015 BTU ~ 1018 J
~
C.Wetzel

Residential
11

Source: U.S. Energy Information Administration
After: LLNL 2010

Rensselaer
CW_2012-06-09_1138.c

Future Chips Constellation

Thermodynamics of a Heat Engine
exergy from heat

dQin = ThotdS
Work out:

W = o P dV

dS = 0
dS = 0

dQout = TcolddS
Entropy S
C.Wetzel

T -T
h = W = Qin - Qout = hot cold
Qin
Qin
Thot
Pressure P

Temperature T

Ideal Carnot cycle efficiency:

CW_2012-06-09_1138.c

Qin
W
Qout
Volume V
wikipedia.org

Rensselaer
Future Chips Constellation

Power Devices now and Future – Strategy of Japan
wide bandgap, silicon, and hybrid

2025 –
Diamond
FET/BJT/PiN/FE
Legend:
FE Field Emitter
IGBT Insulated gate bipolar transistor
SBD Schottky Barrier Diode
SIT Static Induction Transistor
SJ Super Junction

2015 –
SiC
2015 –
GaN

SiC
IGBT/PiN

MOS/SIT/SBD

Performance

HEMT/MOS/SBD

GaAs FET
Power
IC

CMOS, MOSFET (SJ)/SBD, PiN
10

100

Si-IGBT
SiC-SBD, SIC-PiN

Si-MOS(SJ)
SiC-SBD

Si MOSFET (CMOS)
Si
1

2013 – 2035

Si

– 2030

IGBT, Thyristor/PiN

Blocking Voltage
1,000

10,000

after H. Ohashi, Proc. International Symposium on Power Semiconductor Devices and ICs, pp.9-12, June 2012.

C.Wetzel

CW_2012-06-09_1138.c

Rensselaer
Future Chips Constellation

Energy Savings Potential of Solid State Lighting
reverse impact of efficiency boost

Primary Energy U.S.

D W prime

1
Quad
= 94 .6 Quad ´ 0 .40 ´ 0 .21 ´ 0 .42 ´
1 + h / Dh

Tungsten Lamp

2

P= I R
= UI

Data from J. Brodrick, in Illuminating the Challenges DOE 2003,
and DOE EIA U.S. Energy Flow 2009

C.Wetzel

CW_2012-06-09_1138.c

Rensselaer
Future Chips Constellation

Energy Savings Potential of Solid State Lighting
reverse impact of efficiency boost

Data from J. Brodrick, in Illuminating the Challenges DOE 2003,
and DOE EIA U.S. Energy Flow 2009

C.Wetzel

CW_2012-06-09_1138.c

41%

Incandescent
Heat

HID

21%

Fluorescent

Lighting

40%

17%

Incandescent

Electricity
therm

Electricity
electric

Primary Energy U.S.

DW prime

Lighting

D W prime

1
Quad
= 94 .6 Quad ´ 0 .40 ´ 0 .21 ´ 0 .42 ´
1 + h / Dh
= -0.55 Quad /1% -point

42%

5%
Light

Rensselaer
Future Chips Constellation

Epi Chip and Conversion Efficiency
manage thermal load

Pin= U I

heat sink

Ptherm = (1-h) Pin
C.Wetzel

CW_2012-06-09_1138.c

Efficiency

h

Popt = hPin
Image strongly out of proportion

Rensselaer
Future Chips Constellation

Luxeon White LED
epi - chip - lamp

Chip

Epi

Flip chip - style

Lamp
C.Wetzel

I. Ferguson, Please contact author with any referencing errors and they will be corrected
CW_2012-06-09_1138.c

Rensselaer
Future Chips Constellation

Standard Bulb Replacement
fits the socket

Philips

CREE

MR-16

C.Wetzel

LRP-38™
55 Lm/W

I. Ferguson, Please contact author with any referencing errors and they will be corrected
CW_2012-06-09_1138.c

L-Prize Lamp
replaces 60 W
incandescent

Rensselaer
Future Chips Constellation

Composite White Light Emitting Diode
blue plus phosphor

T = 6500 K

solar spectrum

human
eye
visible

0

+ phosphor

blue
LED

400

500

600

p031407a.o p020309a.c

rel. Intensity

1

3k

2k

4k
6k

1k

10k

700

Wavelength (nm)

eye
stimulus
functions
0

blue

400

green
500

red

600

700

1931 Chromaticity Diagram

Wavelength (nm)

fox consulting ClipArtOf.com
©2006 Philips Lumileds Lighting Company. AB08

C.Wetzel

CW_2011-04-18_1231.c
CW_2012-06-09_1138.c

Rensselaer
Future Chips Constellation

Composite White Light Emitting Diode
RGBY LED

T = 6500 K

solar spectrum

human
eye
visible

CW_2011-08-19_1938.c

rel. Intensity

1

schematic
0

400

500

600

3k

2k

4k
6k

1k

10k

700

Wavelength (nm)

eye
stimulus
functions
0

blue

400

green
500

red

600

700

1931 Chromaticity Diagram

Wavelength (nm)

emc.cmich.edu/sunsafety

C.Wetzel

CW_2011-04-18_1231.c
CW_2012-06-09_1138.c

ClipArtOf.com

Rensselaer
Future Chips Constellation

The Challenges in GaInN/GaN LEDs
the hot topics

1.

2.

3.

Efficiency droop

Green gap

Color drift

0.08

0.00

p102605i.c

0.04

0

10

20

30

40

Current Density (A/cm2)

50

0.8

0.6

530

Wavelength

0.12

External Quantum Efficiency (1)

0.16
EQE packaged

Lumileds
Luxeon II
2
1mm

530 nm

(nm)

1.0

0.20

0.4

AlGaInP

GaInN
0.2

520
0.0

400

500

600

Wavelength (nm)

700

0

20
40
Current (mA)

after Osram Dimming InGaN LEDs
after G. Chen et. al, phys. stat. sol. (a) (2008)

C.Wetzel

Rensselaer

CW_2011-04-18_1231.c
CW_2012-06-09_1138.c

Future Chips Constellation

Morphology of MQW
avoid non-uniformity / avoid V-defects
with V-defects

virtually without V-defects
all uniform
Partial Output Power (mW)

well width + 60 %, barrier width + 37 %

TEM

1 mm

GaN + 5 QWs

gro GaN + 5 QWs
1 mm wth

1 mm

8
j = 12.7 A/cm
6

With V-defects
No V-defects
Bulk c-plane GaN

4
2
0
500

GaNro 10 QWs
g +
wth

2

520

540

560

580

600

Dominant Wavelngth (nm)
_

_

+

_

+

Layer
tested

+

_

+ _

_
_

_

AFM
c
4.3 nm

0.4 nm

0.4 nm

Roughness (RMS)

C.Wetzel

after
after
M. Zhu, et al.
C. Wetzel et al.
T. Detchprohm et al.
Phys. Stat. Sol. C, 5, 1777 (2008) Appl. Phys. Lett. 85(6), 866 (2004) Phys. Stat. Sol. C 5(6), 2209, (2008)
CW_2012-06-09_1138.c

P

c-plane

Rensselaer
Future Chips Constellation

Challenge of Crystal Perfection in Green
propagated and generated dislocations
LED
on
sapphire

c

No MDs

Inclined dislocation pairs (IDPs)

Green LED
on bulk GaN
C.Wetzel

M. Zhu et al. Phys. Rev. B 81(12), 125325 (2010). doi:10.1103/PhysRevB.81.125325
CW_2012-06-09_1138.c

Green LED
on sapphire

Rensselaer
Future Chips Constellation

Prospect of Non-Polar Growth
control polarization
P
CBE

CBE

Bandstructure

hn

slow

0

hn

fast

VBE

E

E

VBE

30

0

Growth (Å)

CBE

30

hn

fast
E

VBE
0

Growth (Å)

30

Growth (Å)

Polarization only in-plane

c
m

Crystal
planes P
Takeuchi et al.
Jpn. J. Appl. Phys. 39, 413 (2000)

z

c-plane

y

m-plane

P

CW_2012-06-09_1138.c

a

P

x

C. Wetzel et al.
J. Cryst. Growth 310, 3987-91 (2008).

C.Wetzel

a-plane

Rensselaer
Future Chips Constellation

Homoepitaxy on Bulk GaN - Polar and Non-Polar
replication of bulk quality
Transmission Electron

on c - plane

p-layers

quoted
from a
report to
DOE NETL

on c - plane Microscopy (TEM)

c

MQWs
n-epi GaN

P

growth,
c-axis

GaN substrate

well
barrier
growth,
c-axis

C. Wetzel, et al.
J. Cryst. Growth
310, 3987 (2008)

on m - plane

on a - plane
growth,
a-axis

p-GaN
MQWs

m

p-layers
a-plane

a

P

MQWs
GaN substrate
Q10409B1 LED on a-GaN.p

C.Wetzel

CW_2012-06-09_1138.c

growth,
m-axis

n-GaN
100 nm

m-plane

Rensselaer
Future Chips Constellation

P

Non-Polar m-Plane Green
new dislocations generated

483 nm

516 nm

m

m-plane

C.Wetzel

P
CW_2012-06-09_1138.c

T. Detchprohm et al.
Appl. Phys Lett. 96(5), 051101 (2010)

Rensselaer
Future Chips Constellation

Wavelength Stability with LED Current
stable emission in absence of polarization

EL Intensity (?W/nm)

100

400 mA

Peak Wavelength (nm)

c-plane

c-plane

0.4 mA

10
1

0.1

0.01

10

500
600
Wavelength (nm)

a-plane

EL Intensity (?W/nm)

a-plane

1 mA

1

10

100 mA

0.1

EL Intensity (?W/nm)

1E-3
400

530
a-plane

520

510

m-plane
m-plane

500
1

m-plane

c-plane

100 mA
5 mA

0.1

1
10
2
Currrent Density (A/cm )

100

0.1

0.01

c

m

0.01
P

c-plane

1E-3
400

C.Wetzel

1E-3
400

m-plane

P

500
600
Wavelength (nm)
C. Wetzel and T. Detchprohm, Optics Express 19(S4), A962-A971 (2011) doi:10.1364/OE.19.00A962.

500
600
Wavelength (nm)
CW_2011-04-18_1231.c
CW_2012-06-09_1138.c

a-plane

a

P

Rensselaer
Future Chips Constellation

Wavelength Stability with LED Current
stable emission in absence of polarization
polar growth

20 mA

non-polar growth

current

current

100 mA

c

m

P

c-plane

C.Wetzel

m-plane

P

C. Wetzel and T. Detchprohm, Optics Express 19(S4), A962-A971 (2011) doi:10.1364/OE.19.00A962.
CW_2011-04-18_1231.c
CW_2012-06-09_1138.c

a-plane

a

P

Rensselaer
Future Chips Constellation

Patterned Substrate Epitaxy
length scale and shape

micrometer length scale
Photolithography+
Wet or RIE etching

MPSS

C.Wetzel

nanometer length scale

Nano-imprint
RIE etching

Uniform-NPSS

Natural lithography
Self-assembled Ni island
RIE etching

Non-uniform NPSS

Rensselaer
CW_2012-06-09_1138.c

Future Chips Constellation

GaN on Nano-Patterned Sapphire
profound change in defect structure
LED on nanopatterned substrate

reference LED
500 nm
GaN

TD

GaN

stacking faults

c

c

TD

g=(0002)

voids
Sapphire
Sapphire

500 nm

TD density (plan view TEM):
8

6.4x10 cm

-2

3.6x10 cm

Yufeng Li, et al. Appl. Phys. Lett, 98(15), 151102 (2011).

C.Wetzel

CW_2012-06-09_1138.c

8

-2

-44%

g=[1-100] zone axis
Nano-imprint
on sapphire

Rensselaer
Future Chips Constellation

Capturing Sunlight Efficiently
multijunction cells proposed

2.4

14.9%

13.3%

1.84

16.6%

14.3%

13.9%
1.43
24iakhsfGGG

11.7%

Bandgap (eV)

9.7%

7.8%

0.9

5.0%

3.7%

0.70

4.1%

2.9%

1.12

de-rating
factors

sun spectrum captured
C.Wetzel

Thermodynamic
efficiency

Ideal target efficiency

after: A. Barnett et al., Proc. of 22nd European PV Solar Energy Conf., Milan, Italy, Sept. 2007.
CW_2012-06-09_1138.c

Rensselaer
Future Chips Constellation

A GaInN/GaN Large Gap Junction

100
80
60

2010

2011

progress

40
20
0 CW_2012-07-09_1717.c
340
360

380

400

Current Density (mA/cm2)

External quantum efficiency (%)

top cell in development

1.5 G flux
(suns)

200
100
50
20
10
5
1

progress

7

2

420

Wavelength (nm)

Y. Kuwahara et al.

Mejio-Nagoya Group
C.Wetzel

target : 14%
2012: 3.5%

Y. Kuwahara et al. Appl. Phys. Exp. 4 (2011) 021001, DOI: 10.1143/APEX.4.021001
Y. Kuwahara et al. Appl. Phys. Expr.3 (2010) 111001, DOI: 10.1143/APEX.3.111001
S. Yamamoto, Phys. Status Solidi RRL 6(4), 145–147 (2012), DOI 10.1002/pssr.201206038
CW_2012-06-09_1138.c

Rensselaer
Future Chips Constellation

Acknowledgement
Graduate Students
Yong Xia
Mingwei Zhu
Wei Zhao
Yufeng Li
Zihui Zhang
Shi You
Wenting Hou
Liang Zhao
Yuxin Wang*
Ya Ou*
Christopher Ritacco*
Eylem Kekec*

Postdocs
Alexey Kudymov
Jayantha Senawiratne*
Ibrahim Yilmaz*

Future Chips Constellation, RPI
E. Fred Schubert
S.Y. Lin

Undergraduate Students
Joe Novak
Jennifer Turner
Stephanie Tomasulo
Yena Park* (ECSE)
Eric Williams*
Stephen Gomes* (CS)
Department of Physics, Applied
Physics and Astronomy, RPI
* = previous collaborator

Physics Department, RPI
Prof. M.S. Shur
Prof. P. Persans

Industry
Drew Hanser, Ed Preble, Kyma Technologies,
Raleigh, NC
Leo Schowalter, Crystal IS, Green Island
Funding
Paul J. Severino for Endowment
DOE/NETL Contract of Directed Research DE-FC26-06NT42860, DE-EE0000627
DARPA VIGIL through U.S. Air Force AFRL/SNH FA8718-08-C-0004

NSF Smart Lighting Engineering Research Center EEC-0812056.
C.Wetzel

Rensselaer

CW_2012-06-09_1138.c

Future Chips Constellation

y
vi t

He

ct i

C.Wetzel

lth
a

Energy P
r od
u

Rensselaer
CW_2012-06-09_1138.c

Future Chips Constellation

y
vi t

He

ct i

C.Wetzel

lth
a

Energy P
r od
u

Rensselaer
CW_2012-06-09_1138.c

Future Chips Constellation

y
vi t

He

ct i

C.Wetzel

lth
a

Energy P
r od
u

Rensselaer
CW_2012-06-09_1138.c

Future Chips Constellation

Members and Partners
Full Industrial Members

Affiliate Industrial Members

Innovation Partners

C.Wetzel

Rensselaer
CW_2012-06-09_1138.c

Future Chips Constellation

Bridging

Phosphor-Free White
in Solid State Lighting
Technology
Replace rare earth phophors
Avoid Stokes shift losses
Push for wavelength and power
Polarized emitters
Full spectrum emitters
New defect reduction approach

C.Wetzel

direct emitting GaInN/GaN structures
ultimate benefit of LED
defect reduction by advanced epitaxy
bandstructure design using non-polar growth
yellow and orange, beyond green
nanopatterned growth initiation

Rensselaer
CW_2012-06-09_1138.c

Future Chips Constellation