Contact: peale@mail.ucf.edu

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).