Contact: [email protected]
Cost: $195000 Period: 1-Dec-09 to 31-Oct-11
Plasmonic-Electronic TransductionAFOSR Grant number: FA9550-10-1-0030
Dr. Walter Buchwald
Prof. Robert E. Peale
Presented at AFOSR Program Review, Cambridge MA Dec 2, 2010
Problem
• Optical I/O for plasmonic chips too bulky, no path to large scale integration
• Visible-frequency plasmonics incompatible with IR sensing
Brongersma
Objectives
• Direct electrical (non-optical) on-chip generation and detection of surface plasmons
• IR frequencies for integration with sensing functions
Opportunities• Plasmon-electron
interactions: transducers• Surface plasmon chemical
sensors
MOM tunnel junction
HEMT
INFRARED!!!
MOSFET
DOD relevance
• IR plasmonic smart-sensing• Micro-plasmonic ICs integrated with
standard electronics• Frequency agile detector for LWIR/THz
space situational awareness
Enablers for IR plasmonic applications
• Tight mode confinement– Requires new materials with IR ? p
• Useful coupling resonances– Do they exist?
IR surface plasmon materialsSilicides, Semimetals, Semiconductors, Polymers
Usually need ?’<0, ?”<<|?’| for SPPsCan also get bound SPs when ?’>0 and ?”>>?’.
Polymers
• Surface plasmon excitation on gratings • Polyaniline gives sharpest deepest resonance
Angle of incidence (deg)
Ref
lect
ance
Polyaniline
Chemicals
Oxidize aniline
Dissolve filtered polymer and spin-coat
Monas Shazad
Polyaniline procedure• Determine skin depth• Produce optically thick film• IR ellipsometry to determine
permittivity spectrum• Pattern film into grating• Measure SPP resonances• Compare to theory (Oliner-
Hessel, Jun Peng, Comsol)
1000 2000 3000 4000 50000.0
0.5
1.0
Tra
nsm
ittan
ce
Wavenumber(cm-1)
Polyaniline
Direct electronic-plasmonicinteractions
Electronic detection of plasmons (THz)– MOSFET 2DEG plasmon detected(Allen et al.
1977)– AlGaAs HEMT 2DEG plasmon effects
conductance (Peralta et al. 2002)
• Electronic generation of plasmons (THz)– Hopfel, Vass, & Gornik 1982– Vosseburger et al 1996
Nima Nader
InP-based HEMT
• Push to LWIR (12 THz)• AFRL Hanscom processing• Resonant absorption found at 2x lower
frequency than expected• No resonant electrical photoresponse found
using UCSB FEL– Large non-linear non-resonant response– Large FEL shot variations– $1000/day
Seek mm-wave photoresponse
BWO
CRYO
AFRL
Millimeter-wave induced resonances in ISD
-0.5 -0.4 -0.3 -0.2 -0.1 0.00
20
40
60
80
3/1/10
103 GHz
? f = 0.5 GHz
75 GHz
Lock
-in s
igna
l (?V
)
Gate Voltage (V)
Increased grating period shifts resonance to mm-waves
0 20 40 60 80 100 120 140 160
0.25
0.30
0.35
0.40
Tra
nsm
ittan
ce
Wavenumber (cm-1)
a=10 a=4
a=2a=1
a=0.5
Mm-wave absorption changes with gate voltage
0 20 40 60 800.24
0.26
0.28
0.30
0.32
0.34
0.36
0.38
0.40
Tra
nsm
ittan
ce
Wavenumber (cm-1)
Vg = -0.5
Vg = 0
Absorption changes in BWO range
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.00.24
0.26
0.28
0.30
0.32
0.34
0.36
0.38
0.40
Tra
nsm
ittan
ce
Wavenumber (cm-1)
Vg= 0
Vg = -0.5
BWO frequency modulation with lock-in amplification of ISD
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0-0.09
-0.08
-0.07
-0.06
-0.05
-0.04
-0.03
-0.02
-0.01
0.00
dT/d
f
Wavenumber (cm-1)
Vg= 0
Vg= -0.5
CathodoluminescenceCathodoluminescence
Janardan Nath
• Silver lamellar gratings– Period =20 µm– Amplitude 0.1 to 4.6 µm
• Grating orientations– Perpendicular– Parallel
Resonances in CL spectrumResonances in CL spectrum
?peak=2h/m
400 600 8000
1
2
3
100nm
200nm
1?m
2?m4.3?m
4.6?mN
orm
aliz
ed C
L in
tens
ity
Wavelength(nm)
h
h
mh
peak?
?2
?
4 8 12 16 20400
500
600
700
800
Wav
elen
gth
(nm
)
Peak orders, m
Theoritical 4.6?m gratings 4.3?m gratings 2?m gratings
mh
SPPpeak?
?2
?
4 8 12 16 20400
500
600
700
800W
avel
engt
h (n
m)
Peak orders, m
SPP Theoritical 4.6?m gratings 4.3?m gratings 2? m gratings
Parallel orientation has stronger CL but weaker oscillations, and their phase is shifted by 180 deg
400 600 800
20000
40000
60000
80000
100000
120000 Perpendicular Parallel
CL
inte
nsity
(A
rb. U
nits
)
Wavelength(nm)400 600 800
-0.03
-0.02
-0.01
0.00
0.01
0.02
0.03 Perpendicular Parallel
Der
ivat
ive
Wavelength(nm)
CL spectrum independent of e-beam energy
400 600 800
15000
30000
45000
60000
75000
CL
inte
nsity
(A
rb. u
nits
)
Wavelength(nm)
30 keV 20 keV
Spectra independent of whether one or several grating bars are excited. (Rastered e-beam anyway excites only one bar at a time)
400 600 8000
10000
20000
30000
40000
400 600 800
Parallel
CL
inte
nsity
(A
rb. u
nits
)
Wavelength(nm)
Perpendicular
Parallel
Perpendicular
Excitation outside grating, left and right•CL 10-fold weaker•Independent of distance from grating•Strongest for e-beam to left of grating•Very strong oscillations for perpendicular orientation
4 0 0 6 0 0 8 0 00
1 0 0 0
2 0 0 0
3 0 0 0
4 0 0 0
5 0 0 0
4 0 0 6 0 0 8 0 0
CL
inte
nsity
W a v e le n g t h ( n m )
1 u m ( L ) 2 u m ( L ) 1 u m (R ) 2 u m (R )
L R RL
Excitation outside grating, top and bottom•Almost zero for perpendicular orientation•Symmetric top and bottom•Independent of distance from grating
200 400 600 8000
1000
2000
3000
4000
400 600 800
CL
inte
nsity
Wavelength(nm)
BT 1um (T) 2um (T) 1 um (B) 2 um (B)
T B
Oscillations due to changes in number of collected orders with wavelength?
•Normal emission
• Outcoupling of grazing wave or surface plasmonpolariton (taking Kspp ~ 2?/? ).
am
Sin?
? 1??
)1(1
am
Sin?
? ?? ?
Normal emissionNo oscillations, only stepwise
decrease in CL with wavelength
400 500 600 700 800-20
-16
-12
-8
-4
0
+ 4
+ 8
+ 12
-20
-16
-12
-8
-4
0
+ 4
+ 8
+ 12
Ang
le(d
eg)
Wavelength(nm)
400 600 8000
5
10
15
20
25
0
5
10
15
20
25
Num
ber
of o
rder
s co
llect
ed
b
y th
e m
irror
Wavelength(nm)
Surface wave outcoupling
400 500 600 700 800-20
-16
-12
-8
-4
0
4
8
12
-20
-16
-12
-8
-4
0
4
8
12
Ang
le o
f Acc
epta
nce
(deg
)
Wavelength (nm)Collected orders from left-moving SPP
400 500 600 700 8000
10
20
30
40
SPP moving in +YSPP moving in -Y Total
Num
ber
of o
rder
s of
o
utco
uple
d lig
ht
Wavelength(nm)
Grating pattern
X
Ymirror axis
No oscillations. Only step wise decrease in CL with wavelength
Plasmonic enhancement of thin-film solar cellsAFOSR STTR Phase I
400 600 800 10000.00.51.01.52.02.53.03.54.04.55.0
PowerFilm
Cur
rent
(?A
)
Wavelength (nm)
Before deposition After deposition After wiping surface
Chris Fredricksen
Photoelectron emission microscopy (PEEM) at EMSL/PNNL
Deep Panjwani
Publications in Print• Journal papers• Cleary, Peale, Soref, Drehman, Buchwald, et al. “IR permittivities for silicides
and doped silicon,” JOSA B 27, 730 (2010).• Cleary, Peale, Buchwald et al., “Long-wave infrared surface plasmon grating
coupler,” Appl. Optics 49, 3102 (2010).
• Books and Book Chapters• R. Soref, Buchwald, Peale, Cleary et al, “Silicon Plasmonic Waveguides”,
Chapter 2 in Silicon Photonics for Telecommunications and Biomedical Applications, S. Fathpour and B. Jalali eds. ( Taylor and Francis, UK, 2010).
• J. Cleary, Surface plasmon hosts for infrared waveguides and biosensors, and plasmons in gold-black nano-structured films, PhD dissertation (University of Central Florida, Orlando, 2010).
• Conference publications• Cleary, Peale, Buchwald, et al., “Infrared Surface Plasmon Resonance
Biosensor,” Proc. SPIE 7673, 5 (2010). • Peale, Cleary, Buchwald, et al., “Infrared Surface Plasmon Resonance
Biosensor,” OSA Biomedical Optics (BIOMED) Technical Digest, Paper BTuD104 (ISBN 978-1-55752-887-2, Optical Society of America, 2010).
• Peale, Cleary, Buchwald, et al., “Multi-layer far-infrared component technology,” Proc. SPIE 7817-12 (2010), Invited.
Submissions• Cleary, Peale, Buchwald, et al., “Infrared surface
polaritons on antimony,” JOSA B (2011).• Nath, Peale, Buchwald et al., “Cathodoluminescence
of metal gratings and electron-beam induced current in metal-oxide-metal junctions for plasmonic applications,” Proc. SPIE D&S (2011).
• Shahzad, Peale, Buchwald, et al., “Infrared surface waves on semimetals, semiconductors, and conducting polymers,” Proc. SPIE D&S (2011).
• Cleary, Peale, Buchwald et al., “Optimization of plasmonic resonances in the two-dimensional electron gas of an InGaAs/InP high electron mobility transistor,” Proc. SPIE D&S (2011).