graphene nano-optoelectronicsFrank Koppens

ICFO, The institute of photonic sciences, Barcelona

Graphene research at ICFO

Valerio Pruneri: Optoelectronics•Ultra-thin metal films•Substrate-graphene interactions (doping, switching etc.)

Frank Koppens: group Nano-optoelectronics (~100% graphene)•Nano-optics and plasmonics in graphene•Graphene photodetectons•Graphene phototransistors•Novel hybrid devices

Gerasimos Konstantatos: Solution-processed nanophotonic devicesGraphene phototransistors

Darrick Chang: Theory•Quantum hybrid systems•Graphene quantum nano-photonics

Graphene optical properties

Graphene nano-optics

Graphene optical properties

Graphene opto-electronics and photodetection

Graphene optical propertiesUndoped graphene: Broadband absorption of 2.3%

Nair et al, Science (2008)

Optical conductivity

Graphene optical properties

Undoped graphene

Doped graphene

Bonaccorso et al., Nature Photonics (2010)Li et al., Nature Physics (2008)

Graphene variable transparency

Li et al., Nature Physics (2008)

Reflection

Transmission

nano-optics

Graphene• Gate-tunable optical properties• Ultra-fast (high mobility)• Durable• Flexible • Ultra-thin• Large-scale processing• Patterning with nanometer resolution• ....

opto-electronics

photodetection

Ultra-fast Broadband optical modulator

Liu et al., Nature (2011)

Gate-variable transmission

Graphene as a transparent conductorBroadband transmission Low resistance

Bonaccorso et al., Nature Photonics (2010)

Bae et al., Nature Nanotechnology (2010)

LED and solar cellsSolar cells (inorganic, organic, dye-sensitized)

Light emitting diode

Bonaccorso et al., Nature Photonics (2010)

Graphene mode-locked ultrafast laser

Sun et al., ACS Nano (2010)

Graphene photodetection

Optical communication

CCD

Night viewersSurveillance

On-chip intereconnects

Groups: Novoselov, Geim, Ferrari, Mueller, Lemme, Marcus, Koppens, ....

Two types of photodetectors

Ultra-fastBroadband

Ultra-sensitive

Two types of photodetectors

Two types of photodetectors

Graphene photodetection: broadband and Fast

Mueller et al. Nature Photonics (2010)

Graphene photodetection: broadband and Fast

Dawlaty et al. APL 2008

Absorption Broadband

Mueller et al. Nature Photonics (2010)

Fast (high mobility)

Gate-activated photoresponse: pn-junction

Gate-activated photoresponse: pn-junction

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Lemme, Koppens et al., Nano Letters (2012)Topgate voltage (V)

Photocurrent (nA)

Local on-off control of photosensitivity

➡ Pixelized imaging (infrared camera)

Groups: Marcus (Kopenhagen), Koppens (ICFO), Lemme (KTH)

Efficiency

Responsivity = Iout/Pin1mA/W - 6 mA/W

➡ Absorption 2.3%➡ Intrinsic efficiency ~50% (!!)

➡ Total efficiency 1.1%Mueller et al. Nature Photonics (2010)

Lemme, Koppens et al., Nano Letters (2011)Note: 100% corresponds to ~0.5A/W)

Enhance absorption: metal plasmonics

23Echtermeyer et al, Nature Communications (2012)

• Wavelength selective

• Responsivity enhanced by factor 20 (up to 10mA/W)

Groups: Novoselov, Geim, Ferrari

Ultra-fast Ultra-sensitive

Two types of photodetectors

Hybrid graphene/quantum-dot phototransistor

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Quantum dots:➡Strong absorbers

Graphene:➡High mobility➡Tuneable

Best of both worlds:

Konstantatos,Koppens, under review

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Mechanism: photo-transistor effect

Konstantatos,Koppens, under review

quantum dotgraphene

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Mechanism: photo-transistor effect

Konstantatos,Koppens, under review

quantum dotgraphene

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Advantage 1: Responsive over large area

Konstantatos,Koppens, under review

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Advantage 2: Wavelength selective

Konstantatos,Koppens, under review

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Advantage 3: ultra-sensitive and ultra-high gain➡Responsivity of up to 108 A/W

★Gain of 108

➡ sensitive to optical power of ~fW (3000photons/s)

Konstantatos,Koppens, under review

Backgate voltage (V) Backgate voltage (V)

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Advantage 3: ultra-sensitive and ultra-high gain➡Responsivity of up to 108 A/W

★Gain of 108

➡1 fW of power can be detected (3000photons/s)

Konstantatos,Koppens, under review

Backgate voltage (V) Backgate voltage (V)

Gate tunable

Graphene photodetection

Ultra-sensitive

➡ R > 108 A/W

➡sensitive to ~ 10 fWNEP ~ fW /sqrt(Hz)

Ultra-fast + broadband

➡ R ~ 20 mA/W

➡ f > 20 GHz

Graphene photodetection

Graphene as a platform forstrong light-matter interactions

Nano

Confining light to the nanoscale

Confining light to metals: Circumvent the diffraction limit,

Dielectric

Metal

Sensing

Miniaturization Photonic CircuitsNanoscale opto-electronic circuits

Solar cellsQuantum information processing

Metal Plasmonics

Metamaterials

600  nm

5  nmE=E0*100

E0

Confining light to the nanoscale

Confining light to metals: Circumvent the diffraction limit,

Dielectric

Metal

600  nm

5  nmE=E0*100

E0

Confining light to the nanoscale

Confining light to metals: Circumvent the diffraction limit,

Dielectric

Metal

Graphene: thinnest metal in the world

Graphene Plasmonics

➡Light confinement > factor 150 !!!!➡Gate-tunable plasmon wavelength➡ Gate-tunable nanoscale light switch

Excitation wavelength 5000 nm

Koppens, Chang, Garcia de Abajo (NanoLetters 2011)Nikitin, Guinea, Garcia-Vidal, Martin-Moreno (Arxiv) Gomez-Santos, Stauber, Arxiv (2012)

Vakil et al., Science (2011) Jablan et al, PRB (’09) etc.See e.g. Wunsch (’06), Das Sarma (’07),

Plasmon wavelength = 20-50nm30 nm

Total infrared light absorption!!

Thongrattanasiri, Koppens, Garcia de Abajo (Arxiv 1106.4460)

Resonant plasmon excitation

---> 100% light absorption

Periodic pattern of discs(~ 100 nm diameter)

Recent report in THz regime:Ju et al. Nature Materials (2011)

Sensing

Miniaturization Photonic Circuits

Nanoscale opto-electronic circuits

Solar cells

Quantum information processing

Graphene Plasmonics opto-electronics

Metamaterials

Interconnects

Photodetection

Lasers

LED

Collaborations People

Theory:Javier Garcia de Abajo (CSIC Madrid)

Darrick Chang (CalTech, ICFO)Martin-Moreno (Zaragoza)

Garcia-Vidal (Madrid)Guinea (Madrid)

Leonid Levitov (MIT)

Experiment:Rainer Hillenbrand (NanoGune)

Adrian Bachtold (ICN)Stephan Roche (ICN)

Gerasimos Konstantos (ICFO)Valerio Pruneri (ICFO)

Pablo Jarillo-Herrero (MIT)Charles Marcus (Harvard)

Max Lemme (KTH)Ronald Hanson (Delft)

Lieven Vandersypen (Delft)Cees Dekker (Delft)

Leo Kouwenhoven (Delft)

ExperimentGraphenea (San Sebastian)

Godidnon (CNM)

PI:Frank Koppens

Louis GaudreauMichela Badioli

Fabio GattiGuenevere Prawiroatmodjo

Klaas-Jan TielrooijMarko SpasenovicMark Lundeberg

Group nano-optoelectronics