Graphene Technology: Roadmap to Applications

Transcription

1 Graphene Technology: Roadmap to Applications Andrea C. Ferrari Department of Engineering, Cambridge University, Cambridge, UK

2 Quantum Hall Effect Linear Spectrum Transistors High Mobility? One Atom Thin Membranes/ Gas Barrier Strength Photovoltaics Composites Unique Optical Properties Highly Transparent Stretchable SPECTROSCOPY AND MATERIALS Conductors GROUP 2

3 Bendability of Electronic Materials Material Fracture Strain Material Fracture Strain Silicon ~0.7% Poly- ZnO 0.03% ITO 0.58~1.15% Polyimide 4% Au 0.46% Graphene >15-20%

4 How to Make Graphene? Drawing: ELECTRONIC DEVICES AND MATERIALS GROUP (micro) mechanical cleavage of graphite

5 How to Make Graphene? GRAPHITE IS STRONGLY LAYERED SLICE DOWN TO ONE ATOMIC PLANE ELECTRONIC DEVICES AND MATERIALS GROUP

6 Graphene Production

7 SKKU Process Bae Nature Nano (2010)

8 Industrial graphite purification & exfoliation 10

9 Chemical Exfoliation of Graphene Large area CAMBRIDGE graphene UNIVERSITY coverage 28 April

10 Liquid phase exfoliation graphite + Ultrasonication Ideal case: 100% monolayer graphene flakes

11 Liquid phase exfoliation Dispersion in organic solvent Dispersion in watersurfactant solution Solvent with high surface tension prevents re-aggregations! Surfactant compensates repulsion between water and graphene. Y. Hernandez et al. Nat. Nano. (2008) SPECTROSCOPY AND MATERIALS M. Lotya et al. JACS (2009) GROUP

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13 TEM statistics Liquid phase exfoliation in water Number of flakes N= Number of layers Number of flakes N= Area (nm 2 ) Yield(monolayer)~70%

14 Sorting number of layers via Density Gradient Ultracentrifugation (DGU) Issue: Monolayer, bi-layer, trilayer have same density (ρ)! We exploit the effect of surfactant coverage

15 Sorting number of layers via DGU NOW: Density depends on number of layers After DGU ρ The buoyant density increase with N.. N-layers A. SPECTROSCOPY Green, AND MATERIALS M. Hersam, GROUP Nano lett. (2009)

16 Sorting number of layers via DGU D 2D D Raman shift (cm -1 )

17 Sorting number of layers via DGU 200 nm

18 Ink-Jet Printing Graphene-Ink

19 Deterministic Placement On Si/SiO 2 On Optical Fiber

20 BILAYER TWIST Overlap Bottom Intensity [A.U.] OVERLAP TOP Top BOTTOM Raman shift [cm-1]

21 Wafer Scale Graphene Transfer Mechanical Support/Graphene/Ni(or Cu)/SiO 2 peeling off in water Ni (or Cu) Rapid etching with FeCl 3 (aq) Graphene on polymer support Post-patterning SiO 2 Transfer Pre-patterning Patterned graphene on Ni Patterned graphene on arbitrary substrate Patterning Graphene on arbitrary substrate Kim et al Nature 2010

22 Wafer Scale Graphene Devices 16,200 FET devices L C : 10 μm L W : 5 μm Y. Lee et al. NanoLett., 10, 490 (2010)

23 Graphitic Carbon For LHC

24 Preparation for SPS magnet prototype graphitic coating

25 Gas barrier diffusion properties Gas Diffusion Barrier Barrier to oxygen Barrier to CO 2 gas CO 2 O 2 AA H 2 O Migration of flavors Industrial specifications compatible with blow molding production rate few seconds Deposition time Packaging regulation Recyclable food contact safe

26 Thickness distribution Uniformity = ± 15% Thickness (nm) C 2 H 2 : 160 sccm MWP: 350 W T1 : 1 s T2 : 1 s P1 : 50 mbars P2 : 0.1 mbars Point Vd = 60 nm/s

27 25,0 20,0 PET a-c:h 60 nm a-c:h : 150 nm CSD - CSD (17.5% of CO 2 loss) - 44 weeks with 60 nm a-c:h %CO2 Loss 15,0 10,0 Beer - 52 weeks with 150 nm a-c:h - Beer (10% of CO 2 loss) -25 weeks with 60 nm a-c:h -30 weeks with 150 nm a-c:h - Non coated PET bottle - 4 to 10 weeks shelf life 5,0 0,0 Shelf life (weeks) 0,0 10,0 20,0 30,0 Time (weeks) 40,0 50,0 60, Thickness(nm)

28 Bunch,McEuen, Nano Lett 2008 Graphene Balloon

29 Composites Strain Sensor

30 Optical micrograph Optical properties Confocal Rayleigh map Graphene can be visualized optically Casiraghi, C. et al Nano Lett. 7, 2711 (2007). The optical image contrast scales with the number of layers

31 Optical properties Universal optical conductance G 0 = e 2 /4ħ Ω 1 T = ( πα) 2 1 πα 97.7% A=1-T=πα=2.3% SLG reflects << 0.1% of the incident light in the visible region, raising to ~2% for 10 layers Nair Science 2008 Kuzmenko PRL 2008

32 ITO drawbacks Increasing cost due to Indium scarcity Processing requirements, difficulties in patterning Sensitivity to acidic and basic environments Brittleness Wear resistance

33 ITO replacements 100 Transmittance (%) ITO ZnO/Ag/ZnO TiO 2 /Ag/TiO 2 Arc discharge SWNTs Wavelength (nm) Metal grids, metallic nanowires, metal oxides and SWNTs have been explored as ITO alternative

34 100 Transmittance (%) Graphene ITO ZnO/Ag/ZnO TiO 2 /Ag/TiO 2 Arc discharge SWNTs Wavelength (nm) Graphene films have higher T over a wider wavelength range with respect to SWNT films, thin metallic films, and ITO

35 For n 0, σ dc,min 4e 2 /h R s 6kΩ/ for an ideal intrinsic SLG with T 97.7% Thus, ideal intrinsic SLG, would beat the best ITO only in terms of T, not R s

36 100 Transmittance (%) n=3.4x10 12 cm -2 μ=2x10 4 cm 2 / Vs R s (Ω/sq) LPE RGO PAHs CVD MC Graphene calc.

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38 Graphene-based flexible smart window

39 Rod coating Graphene dispersion Rod coater PET film Wire winding Substrate Graphene dispersion

40 Transparent conductor On PET ~ 500Ω sheet resistance ~ 80% transparency

41 Polymer dispersed Liquid Crystal: Schematic Flexible, transparent Polymer support Polymer dispersed Liquid Crystal Graphene based transparent electrode Graphene based transparent electrode Polymer dispersed Liquid Crystal V V Flexible, transparent Polymer support

42 Touch screens The TC requirements for touch screens are R s Ω/ and T>90% Considering the R s and T required, GTCFs produced via LPE offer a viable way towards low cost devices

43 Wafer-Scale Synthesis and Transfer Transparent graphene film 4 inch scale graphene film on Stretchable Substrate Patterned GrapheneDEPARTMENT film OF 4 ENGINEERING inch scale graphene film SPECTROSCOPY AND on MATERIALS GROUP on PET Flexible Substrate

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45 SKKU Touch screen Bae, S. et al. Nature Nano (2010)

46 Flexible, Foldable AMOLED Display Touch Screen Anode (ITO) TFT OLED Cathode Substrate Front Plane : Touch Screen, OLED Back plane : TFTs

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48 Photovoltaic devices Graphene can fulfil multiple functions in PV devices: 1) Transparent conductor window 2) Photoactive material 3) Channel for charge transport 4) Catalyst

49 Silicon solar cells Silicon solar cells dominate the current PV technology η up to ~25% Graphene TC Films can be used as window electrodes in inorganic solar cells

50 Organic solar cells Transparent conductor window Photoactive material η > 12% could be possible Yong, V.,Tour, J. M. Small 6, 313 (2009)

51 Dye Sensitized Solar Cell O'Regan and Gratzel, Nature, 252, 737 (1991) Transparent conductive electrode Graphene bridge structure I 3 - I - I - I 3 - Counter electrode

52 DSSCs assembly Graphene electrode is prepared by drop casting the dispersion on quartz substrate

53 Graphene based PDs (GPDs) Photodetectors Avouris, et al. GPDs can work over a much broader wavelength range GPDs have a faster response compared to traditional PDs

54 Graphene for photodetection high mobility and Fermi velocity potentially allow high operating speeds f t 40 GHz / 10 Gbit/s demonstrated absorption of 2.3 % per layer constant over the visible range to the infrared zero band-gap semiconductor no cut-off wavelength dark current Mueller et. al., Nature Photonics 4, 297 (2010). Nair et. al., Science 6, 5881 (2008).

55 Working principle e-h pair creation e-h Metal-induced separation doping Metal Giovanetti et. al., Phys. Rev. Lett. 101, (2008).

56 Light emitting devices Organic light emitting diodes (OLED) TC films based on graphene and graphene oxide have been demonstrated for OLED and light-emitting electrochemical cell Electroluminescence observed in graphene could lead to novel emitting devices based entirely on graphene Essig, S. et al. Nano Lett. 10, 1589 (2010)

57 Making Graphene Photoluminescent

58 3s, scale 5μm

59 PL Elastic Scattering

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61 Broadband Nonlinear PL PL e-e relaxation (~100fs) Optical pumping Cooling by phonon emission (~1ps)

62 Broadband Nonlinear PL Elastic light scattering image Nonlinear PL image Red and Blue PL, as result of e-e collisions Heinz+Wang+Sthor+Hartschuh SPECTROSCOPY AND MATERIALS 50 x 50 µm GROUP 2

63 Ultrafast lasers Mirror Mirror Laser gain media Saturable Absorber CW Ultrafast Pulses < second A saturable absorber turns a continuous wave (CW) laser into an ultrafast laser Mode-locked laser produces: Ultra-short Pulse Duration Enhanced Peak Power Wide Spectrum

64 Applications of mode-locked lasers Normal Cancerous CAMBRIDGE Essential UNIVERSITY tools for cutting-edge research in Physics, DEPARTMENT Engineering, OF ENGINEERING Chemistry, Biology, Nanotechnology

65 The effect of a saturable absorber First, imagine raster-scanning the pulse vs. time like this: Intensity Short time (fs) Round trips (k) k = 1 k = 2 k = 3 k = 7 After many round trips, even a slightly saturable absorber can yield a very short pulse. Notice that the weak pulses are suppressed, and the strong pulse shortens and is amplified.

66 Problems with current technology Current technology of Semiconductor Saturable Absorber Mirrors (SESAM) requires molecular beam epitaxy growth of GaInAs/GaAs heterostructures ion implantation (Ni, Be, etc) to reduce relaxation time can work only in reflective mode

67 Graphene as an ultrafast ultrawide band saturable absorber e-e relaxation (~100fs) Cooling by phonon emission (~1ps) Optical pumping

68 Exploiting the wide graphene absorption band: Wavelength tunability Graphene Normalized Intensity nm 1534nm 1541nm 1547nm 1553nm 1559nm Absorbance (a.u.) CNTs Wavelength (nm) Wavelength (nm) Wavelength (nm) Z. Sun et al. Nano Research (2010) 70

69 Ultrafast laser Graphene-SMMA polymer composite Highly-doped Er 3+ fiber WDM Pump laser ISO Coupler PC Output Graphene mode-locker SPECTROSCOPY AND Z. Sun MATERIALS et al. ACS GROUP nano 4, 803, 2010

70 Graphene Mode-locked Laser

71 Wavelength-tuneable Graphene Mode-locked Laser

72 Quantum Hall Effect Linear Spectrum Transistors High Mobility? One Atom Thin Membranes/ Gas Barrier Strength Photovoltaics Composites Unique Optical Properties Highly Transparent Stretchable SPECTROSCOPY AND MATERIALS Conductors GROUP 74

73 Potential of Graphene Flexible Display Touch Panel Conductive ink EMI screen ink High speed Transistor RFIC, Sensor Graphene Dispaly /Solar cell Packag Solar cell Battery Supercap. LEDlighting, BLU Automobile ECU PC Automobile Air plane components Science Engineering Technology

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75 D.M. Basko E. Lidorikis A.Hartschuh H. Qian T. Gokus T. Ryhanen S. Lacour J. Kivioja A. Colli P. Beecher Z. Radivojevic P. Chiggiato M. Taborelli Thanks to K. S. Novoselov A. K. Geim Jong-Hyun Ahn Byung Hee Hong A. Lombardo B. Bonetti T.J. Echtermeyer Z. Sun D. Popa S. Piscanec F. Bonaccorso G. Calogero T. Hasan G. Privitera F. Torrisi T. M. G. Mohiuddin R. R. Nair C. Galiotis

76 Acknowledgements