high power high efficiency duv leds and...
TRANSCRIPT
LED TAIWAN IR+UV SUMMIT 2016
- High Power High Efficiency - DUV LEDs and Applications
James Wu Research and Development Qingdao Jason Electric Ltd Qingdao, 266101 China
April 14th 2016 TWTC Nangang Exhibition Hall
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Presentation Outline
1. Introduction
2. Development and Performance of DUV LEDs
3. Applications for DUV LEDs
4. Conclusions
Qingdao Jason Electric Ltd 2
Background of QD Jason
1. Founded on 2001
2. 2001-2008 focusing on HT AlGaN-MOCVD equipment R&D and manufacture
3. 2009 moved to development of DUV LEDs using homemade MOCVD
4. 2013 started to ship DUV LEDs samples with miliwatt power
5. 2014 awarded BSI ISO9001:2008 Quality Management System certificate
6. 2015 acquired by Epitop Technology Inc of China
7. Epitop Technology Inc is a top 5 visible LEDs maker in mainland China
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Applications on UV LEDs
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Nail manicure Bills ID Check
UV-B
UV-A
UV-C
phototherapy
DNA Sequencing
Air purification
Food sterilization
Water Purification
Ozone Monitering
Healthcare
Ink printing
Agriculture
Curing
Global UV LEDs Technology Market
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Snapshot Summary of Trends and Drivers
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1. Growing in food ,workspace and air sterilization drives market expension
2. Ban on mercury based lighting solutions benefits the UV LEDs technology
3. Curing applications to generate a Chuck of Market Revenue
4. UV LEDs continue to gain widespread popularity in inkjet printing
5. Development of UVB LEDs phototherapeutic devices to spur opportunities in the healthcare sectors
6. Strong growth in UVC consumer electronics to bring in new market
opportunity
Role Players of DUV LEDs (<=310nm)
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China
South Korean
Japan USA
u Nikkiso u Akasaki u Tokuyama
u SETI u Rayvio u Crystal IS
u LG Innotek u Soul Viosys
u Qingdao Jason
l Nikkiso 50mW @ 350mA production at 2016 l Tokuyama 90mW@350mA R&D l SETi 30mw@350mA production l Akasaki & Crystal IS 20mW@400mA l Rayvio 45mW R&D l QD Jason Ltd 176mW@1A R&D, 5-20 mW production
More visible LEDs makers may move toward DUV LEDs
Advantages of UV LEDs
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1. Customerizable UV light source
2. Green energy and environmental friendly with no mercury filled
3. Instant On/Off no warm up time
4. Longer life time compared to mercury lamp
5. Easy integration with lower voltage and small dimension
6. No ozone production
Compared to Conventional UV Light Source UV LEDs has Significant Advantages
UV LEDs Design
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DUV LED
Ø Bandgap Engineering is the basic of DUV LEDs design
Ø 255nm to 350 nm UV LEDs is realized by combination of AlGaN material system
UV LEDs Structure and Challenges
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Sapphire /AlN
n+-AlGaN buffer
MQW
p-AlGaN
p+-GaN
SL
Ø Flip Chip Structure
Ø Sapphire heating dissipation
Ø AlN transparency
Ø AlN buffer quality and thickness
Ø P-GaN absorption
Ø Contact electrode absorption
Ø Defects density cause low IQE
Ø Low EQE
Go vertical
Remove substrate
Nano pss/ELO
P-AlGaN contact
Reflective
Quality
LEE+IQE
IQE Improvement Approach
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AlN quality and whole DUV LEDs structure quality is the key to improve IQE
Growth of DUV LEDs on Sapphire remains to be a challenge!
Bulk AlN Substrate AlN ELO Thicker AlN Template
DD- 105cm-2 DD- 108cm-2 DD- 109cm-2
Ø HVPE Template Ø MEMOCVD Template
LEE Improvement Approach (1)
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• Sapphire substrate with Moth-eye pattern on back side Ø On wafer Improvement of Output Power by×1.5 • Hybrid nano photonic pattern on back side of AlN substrate by HVPE Ø High power with high efficiency 265nm
“Light extraction enhancement of 265 nm LED with over 90 mW output power via an AlN hybrid nanostructure”
C.Pernot, M. Kim, S. Fukahori (APE 2010) S-I Inoue, T. Naoki (APL 106 2015)
LEE Improvement Approach (2)
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Trade Off Between LEE and Ø There is a trade off between voltage and LEE improvement Ø Loss of ohmic contact resistance on P side material
Reflective Electrode Design
Max Shatalov, W-H Sun etl, SETi
Transparency no P-GaN design
Lobo et al. Appl. Phys. Lett. 96, (2010) 081109
LEE Improvement Approach (3)
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Han Youl Ryu,nano scale research letters, 2014
Ø Nano Rod UV LEDs Structure is expected to improve LEE up to 50% according to Han’s simulation
LEE Improvement Approach (4)
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Encapsulation
Ø Encapsulation can improve light extraction efficiency
Ø However usually most resins are decomposed under DUV light
Ø Studying under DUV range is still underway
“Development of underfilling and encapsulation for deep-ultraviolet LEDs “ K. Yamada, Y. Furusawa, S. Nagai, Amano Hiroshi, Akasaki Isamu Applied Physics Express, Volume 8, Issue 1, 2015
Trade off between encapsulation and reliability!
Low Voltage High Power 280nm UV LEDs
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Ø 176mW optical power was achieved at 1A dc operation for single 4545 device Ø 46 mW optical power at 200mA for 1515 device Ø Voltage is as low as 5.8V at 1A for 4545 device Ø Differential resistance is less than 1 ohm at high current
ü Encapsulation ü Reflection on Packaging ü High quality AlN Template ü Thicker and quality N-AlGaN ü Good ohmic contact for N and P ü Good heat dissipation
0 200 400 600 800 10000
20
40
60
80
100
120
140
160
180
200
Power Voltage
Current (mA)
Pow
er (m
W)
small die IV
large die IV
large die L-I
small die L-I
0
1
2
3
4
5
6
7
8
9
10
Vol
tage
(V)
CW 280nm UV LEDs
Low Voltage High Power 280nm UV LEDs
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Ø 5% EQE for 4545 small device Ø 8% EQE for 1515 large device
0 100 200 300 400 500 600 700 800 900100011000
25
50
75
100
125
150
175
Current (mA)
Pow
er (m
W)
small die L-I
0
2
4
6
8
EQE&
WPE
%
EQE
WPE
L-I
WPE
EQE
large diesmall die
Efficiency droops faster for smaller device
Stress for 280nm UV LEDs
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Ø over 3000 hrs was measured at 20mA for 1515 device Ø estimated L50 is about 8000 hrs
0.1 1 10 100 1000 1000020
30
40
50
60
70
80
90
100
Rela
tive
Pow
er (%
)
Stress Time (Hrs)
Nikkiso’s 285nm UV LEDs
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Ø Over 10000 hrs life time achieved at L70! Ø Driving current affects life time of DUV LEDs
DUV LEDs Application
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Dis
infe
ctio
n ef
ficie
ncy
Wavelength
Ø 265-270nm has the best disinfection efficiency
DUV Applications
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Ø Water Disinfec-on • UVC LEDs has effec.ve penetra.on in water • Portable water Steri Pen • Drinking water machine • Air Purifier
Drinking Water
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Sta-c Water Disinfec-on Experiment
1 Liter Water Cup with UVC Disinfec-on Module 1 Liter water Cup without UVC Module
Experiment Details: • UCV module with1mW power was set up on for 2mins once a hour for disinfection • For the first two days every 24 hrs take 0.1ml water sample for experiment • From 3rd day to 7th day every 12 hrs take 0.1ml water sample for experiment
UVC Module No UVC
Water Level Water Level
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Disinfec-on Experiment Data
图9深紫外抑菌模块抑菌对比图
UVC Irradiation
No UVC Irradiation
Bac
teria
l cou
nt
• UCV LEDs Module can effectively prevent bacterial from growing • Without UVC irradiation the water easily reach to high level of bacterial
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Flowing Water Instant Disinfec-on Experiment
• 2 UVC LEDs Units can be installed at water inlet and outlet for instant disinfection
After Before
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Air Disinfec-on Module
UVC LEDs Arrays Module Air Purifier
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Air Disinfec-on Module Explosion Structure
UVC LEDs Module
Filter Fan
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Food Disinfec-on Module and Experiment
Ø Improving foods lifetime Ø Removing order Ø keeping fresh
UVC LEDs Module For Fridge
Upper Level No UVC
Bottom Level with UVC
Mouldy
No mouldy
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Medical Instrument and Health Care
UVC Sanitizing Toothbrush Case
UVC Scanner UVC Contact Lens Case UVC Bandage
Conclusions
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Thank � You � For � Your � Attention! � �
• DUV LEDs has advantages compared to conventional mercury lamp
• We have achieved high efficiency and high optical power DUV LEDs • Record high output power of 170mW at 1A was achieved due to high material quality and good device fabrication and good encapsulation and packaging • DUV LEDs applications have been becoming real now.