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A Science & Technology Center
Theme III: NanophotonicsFor Energy-Efficient Communications
Theme Leader: Ming C. Wu
E3S RetreatSeptember 20, 2018
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A Science & Technology Center
Optical antenna-enhanced nanoLED
Electrical injection III-V antenna-LEDs [Wu, Yablonovitch, UCB;
Kim/Fitzgerald, MIT]
Monolayer TMDC antenna-LEDs[Wu, Yablonovitch, Javey, UCB]
Current Theme Projects & PI’s
Ultra-sensitive photoreceivers
Photoreceiver analysis [Yablonovitch, Yablonovitch, UCB]
Photo-bipolar junction transistor (BJT) [Chang-Hasnain, UCB;
Fitzgerald, MIT]
Link modeling and system analysis[Stojanovic, UCB]
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Team Members Theme III inter-institutional postdoc
Seth Fortuna
Graduate Students: Matin Amani, Nicolas Andrade, Sujay Desai,
Kevin Han, Sean Hooten,
Jonas Kapraun, George Zhang, Peida Zhao (UCB)
Undergrad: Joy Cho (UCB)
Postdocs: Der-hsien Lien, Kyungmok Kwon
Alum Chris Heidelberger (MIT-Lincoln Lab), Indrasen Bhattacharya
(KLA-
Tencor), Kevin Messer (Magic Leap), Christopher Keraly (PARC),
Ryan Going (Infinera), Michael Eggleston (Bell Labs), Wilson Ko
(OURS), Yue Lu (Qualcomm)
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Theme Overview• Main goal: Dramatically improve the interconnect
energy
efficiency to 20 aJ/bit @ 20 photons/bit (Current state of the
art: 100s fJ/bit @ 10,000 ph/bit)
Antenna-LED
Si Photonic Waveguide
NanoPhototransistor
Antenna-Enhanced LED• No threshold (DC bias)• Use optical
antenna to enhance
spontaneous emission rate• Faster than laser
Ultra-Sensitive Photoreceivers• Ultralow capacitance (<
100aF)
to enlarge photo signal• Integrate PD with first gain
stage to eliminate wire capacitance
Our Approach
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Progress of Antenna LED under E3S
OpticalPumping
ElectricalInjection
III-V III-V
TMDC
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Focus shift to • Temporal response• Efficiency• Output power
TMDC
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Electrically-injected III-V antenna-LED
nanoLED ridgeinterconnect
Ag
cavity-backed slot antenna250nm
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No antenna
Antenna-Enhanced Electroluminescence
No antenna
Antenna-LED
n
p
n
p
Fortuna et al. ISLC 2016
Seth Fortuna
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50 Picosecond Spontaneous Emission Lifetime
antenna-LED
rad = 1.6 nsτno antenna
T=77K
rad = 50 psτ
Fortuna et al. ISLC 2018
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First Demonstration: Integration of Slot Antenna with Colloidal
Quantum Dots
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Au
3 µm
Photoluminescence image
Slots with CdSeS/ZnSquantum dots
Laser spot
Slot
Off-slot
Seth Fortuna, Michael Bartl, Vladimir Bulovic, et al.
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Waveguide Coupled Antenna-LED schematic
Top-view: cross-section along cutline
Perspective view
Cross-sectional view
Andrade et al. CLEO 2018.
NicolasAndrade
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Inverse Design Waveguide Coupler
y
x
Ag
InP
nanoLED
Tapered Coupler After Optimization
Top View Cross-section
Top View Cross-section
Andrade et al. CLEO 2018.
NicolasAndrade
Sean Hooten
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Inverse Design Power Flow
Cross section of power flow coupled to single mode InP
waveguide
InP
AgAir
x
z200nm
nanoLED
SOG
Cross section of power flowon bulk InP
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ID: High Power
ID: High Speed
Tapered Coupler
Bulk
Inverse Design Optimization
ID: High Power
ID: High Speed
Tapered Coupler
Bulk
Average Enhancement: 168.9Average Waveguide-Coupled EQE:
60.8%
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Metal-Dielectric Antenna
0Gap d (nm)
Effic
ienc
y
d
Si
20nm
Ag
5 10 15 20
d20nm
0%
25%
50%
75%
100%
Metal-Dielectric
All MetalEn
hanc
emen
t
103104105106107
0Gap d (nm)
5 10 15 20
Sean Hooten
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Metal-Dielectric Antenna LEDb
b
50nm
20nm
20nm
50nm
50nm Cylindrical
Lithographically Patterned
Electrical injection compatible High efficiency (~70%)
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Bridge Width b (nm)
b
InP
bInP
Enha
ncem
ent 104
105
103
102100 20 30 40
Metal-Dielectric Antenna LED
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Electrical Injection LED with Monolayer WSe2 Emitter
Device Device lifetime Brightness External quantum
efficiencyDual-gated PIN diodeDC; no solventArea ~ 20 um2
30 min ~400 pW >10-4
Pulsed device 1(8 kHz)
Pulsed device 2(8 kHz)
DC dual-gate device
Current (nA)
Coun
ts/s
L-I curves
p++ SiAg gate + reflector
Al2O3 (60 nm)
Au contact
Au contact
WSe2
p++ SiAg back reflector
Al2O3 (60 nm)Au gate Au gate
WSe2hBN
Pt contact
Ni contact
Old dual-gate New single-gate VnVp
Kevin Han
In collaboration with Javey Group
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High efficiency Monolayer WSe2 LEDs
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~
+-
~Vp
Vn
Vg +
IQE
(%)
Equivalent current (nA)
PL
EL
Equivalent current (nA)
Out
put p
ower
(nW
)
ELPL
Process improvements yield EL efficiency close to PL
(~1%),indicating material-limited efficiency
N contactP contact
Al2O3WSe2
5 um
Kevin Han
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EL long-term stability
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Time (s)
Inte
nsity
(cou
nts/
s)
EL with pulsed injection is stable over hours
Pulsed injection20 kHz
DC injection
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Summary
First temporal measurement of III-V antenna-LED 50 ps
spontaneous emission lifetime measured at 77K Compared with 1.6 ns
without antenna
High coupling efficiency to single mode waveguide by inverse
design Overall efficiency > 60% (including metal loss)
First demonstration of quantum dot emitters with slot antenna
Electrical bipolar injection LED with monolayer WSe2 Very sensitive
method to characterize surface recombination
velocity Collaboration with Jesús del Alamo group
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Theme III: Nanophotonics �For Energy-Efficient
CommunicationsCurrent Theme Projects & PI’s�Team MembersTheme
OverviewProgress of Antenna LED under E3SElectrically-injected
III-V antenna-LEDAntenna-Enhanced Electroluminescence 50 Picosecond
Spontaneous Emission LifetimeFirst Demonstration: Integration of
Slot Antenna with Colloidal Quantum DotsWaveguide Coupled
Antenna-LED schematicInverse Design Waveguide CouplerInverse Design
Power FlowInverse Design OptimizationMetal-Dielectric
AntennaMetal-Dielectric Antenna LEDSlide Number 16Electrical
Injection LED with Monolayer WSe2 EmitterHigh efficiency Monolayer
WSe2 LEDsEL long-term stabilitySummary
