Graphene adhesion underhigh pressure

Alfonso San Miguel

J. Nicolle, D. Machon, Ph. Poncharal, O. Pierre-Louis

Laboratoire de Physique de la Matière Condensée et NanostructuresUniversité de Lyon 1 et CNRS

Probing graphene adhesion

Measure of graphene adhesion energy

Adhesion energy :0.45 ± 0.02 J m−2 for monolayer graphene0.31 ± 0.03 J m−2 for samples containing two to five graphene sheets

S.P. Koenig et al, Nature Nanotechnology 6, 543–546 (2011)

Graphene under high pressure

J. Nicolle, D. Machon, P. Poncharal, O. Pierre-Louis and A. San Miguel

Nano Letters 11, 3564 (2011)

Graphene Raman signal

1200 1400 1600 1800 2400 2600 28000

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

5500

6000

Inte

nsity

(a.u

)

Raman shift (cm-1)

Raman of a single layer sample

G2D

D

Experimental : Raman in DAC

G 2D

Grap

hene

Bila

yer

λ =647.1 nm

1400 1600 2600 2800

R am an sh ift (cm -1)

1400 1600 2600 2800

Raman shift (cm -1)

Ambient Pressure

P=1.0 GPa

P=2.4 GPa

P=3.5 GPa

(i)

(i)

(X5)

(X2)

(b)

(i)

(i)

(i)

(i)

G

G

G

G2D

2D

2D

2D

1400 1600 2600 2800

Raman shift (cm -1)

(i)

1400 1600 2600 2800

Ram an shift (cm -1)

Ambient Pressure

P=2.4 GPa

P=5.0 GPa

P=7.0 GPa

(i)

(a)

(i)

(i) (i)

(i)

G

G

G

G

2D

2D

2D

2D(X5)

(X2)

(X2)(X2)

1400 1600 2600 2800

R am an sh ift (cm -1)

1400 1600 2600 2800

Raman shift (cm -1)

1400 1600 2600 2800

R am an sh ift (cm -1)

1400 1600 2600 2800

R am an sh ift (cm -1)

1400 1600 2600 2800

R am an sh ift (cm -1)

1400 1600 2600 2800

Raman shift (cm -1)

Ambient Pressure

P=1.0 GPa

P=2.4 GPa

P=3.5 GPa

(i)

(i)

(X5)

(X2)

(b)

(i)

(i)

(i)

(i)

G

G

G

G2D

2D

2D

2D

1400 1600 2600 2800

Raman shift (cm -1)

(i)

1400 1600 2600 2800

Ram an shift (cm -1)

Ambient Pressure

P=2.4 GPa

P=5.0 GPa

P=7.0 GPa

(i)

(a)

(i)

(i) (i)

(i)

G

G

G

G

2D

2D

2D

2D(X5)

(X2)

(X2)(X2)

G-band position with pressure(PTM: 4:1 methanol ethanol)

G-band pressure slope

Graphene Raman G-band in hydrostatic conditions

Hooke law for an hexagonal system:

000

2 1211

44

44

331313

131112

131211

z

xy

zx

yz

zz

yy

xx

SSS

SSSSSSSSSS

In-plane Biaxial deformation: (z = 0)

..2 12112 SSD

In-plane Triaxial deformation: (z = )

..2 1312113 SSSD

11.5.7 GPacmPG

11.0.4 GPacmPG

BIAXIAL

TRIAXIAL

but why so … ?

Substrat (Si+300 nm SiO2)

What can be expected ?

can the substrate tract (at least partially) graphene ?

Graphene on SiO2

AFM: High-Fidelity Conformation of Graphene to SiO2 Topographic Features (99%)

SiO2 substrate

W.G. Cullen et al., PRL 105, 215504 (2010)

rms ~ 0.35 nm

O. Pierre-Louis, Phys. Rev. E 78, 021603 (2008)

Adhesion of a membrane on a sinusoidal surface

Perfect adhesion

Unbinding

A very familiar phenomena

1 2 3 4 5 60.0

0.5

1.0

1.5

2.0

2.5

3.0

Number of layers (n) =(keq/kg)2

kg : typical substrate curvaturekeq=(2gn/Cn)1/2 is the adhesion equilibrium curvature

gn : multilayer graphene adhesion energy on SiO2

Cn : bending rigidity.

Calculatedunbinding transition

Unbinding between n=2 and 3

BIAXIAL

TRIAXIAL

BIAXIAL

TRIAXIAL

Why this difference of~ 3 – 3.5 cm-1 GPa-1 ???

0 1 2 3 40

20

40

60

80

100

120

140

160

0 1 2 3 40

20

40

60

80

100

120

140

160

2D (P

)-2D (0) (cm

-1.GP

a-1)

2D1B

2D(P

)- 2D

(0) (

cm-1.G

Pa-1

)

Pressure (GPa)

2D1A

2D2A

2D2B

Alcohol Argon

2D

1B

2D1A

2D2A

2D2B

Splitting of the bilayer 2D band:an indication of doping

ArgonAlcohol

Predicted by: C. Attaccalite et al., Nano Letters 2010, 10, 1172-1176.

0 1 2 3 4 5 6 7 8

0,0

0,5

1,0

1,5 1 layer 2 layers

I(2

D)/I

(G)

Pressure (GPa)

Argon

I(2D)/I(G) evolution

0 1 2 3 4 5 6 7 8

0,0

0,5

1,0

1,5

Alcool

1 layer 2 layers 1 layer 2 layers

I(2D

)/I(G

)

Pressure (GPa)

Argon

I(2D)/I(G) evolution

Pressure effect

High pressure induced doping

A. Das et al., Nat Nano 2008, 3, 210-215.

n PTMn/ P (x1013)

(cm-2 GPa-1)

1alc. 0.70.2Ar 0.2 0.2

2alc. 0.80.2Ar 0.1 0.2N2 0.1 0.2

High pressure induced dopingn ~ 5 x1013 cm-2 at 7 GPa

(EF ~ 1 eV)

Doping effect on the G-band

Graphene : A. Das et al., Nat Nano 2008, 3, 210-215.Bilayer: A. Das et al., Phys. Rev. B 79, 155417 2009

Pressure effect

)(

6.31

grapheneGPacm

PG

)(

4.31

bilayerGPacm

PG

A last question : why no-doping for n=3 in alcohol ?

Substrate mediated doping !

Substrate mediated dopingby silanol groups

Si–O–H groups as e- donors

Si–O–Si + Alcohol → Si–O–H

Lee et al. J. Phys. Chem. C Lett. 111, 12504 (2007)

Conclusions

• Adhesion or unbinding decides on the graphene pressure behavior (2D vs 3D)

• Adhesion/unbinding transition observed between n=2 and n=3 (n =2 is different !!)

• Extreme surface P-mediated doping in alcohol

in the adhesive configurationApplications: pressure/stress sensors

n PTM

n/ P

(x1013)

(cm-2 GPa-1)

[G/ P]dop

(cm-1 GPa-1)

G/ P

(measured)

(cm-1 GPa-1)

[G/ P]mech

(cm-1 GPa-1)

1alc. 0.70.2 3.61.1 10.50.2 6.91.4

Ar 0.2 0.2 1.0 1.1 7.6±1.0 6.6 2.0

2

alc. 0.80.2 3.41.1 10.40.3 7.01.4

Ar 0.1 0.2 0.3 0.6 6.9±1.0 6.6 1.6

N2 0.1 0.2 0.3 0.6 6.9±0.2 6.6 0.8

Doping and mechanical (bi-axial, n=1,2) pressure effects

2550 2650 2750 2550 2650 2750

l=514 nm l=647.1 nm

n=1

n=2

n=3

n=4

n=5

HOPG

HOPG

n=5

n=3

n=2

n=1

(a) (b)

n=4

2D band: Identification of the number of layers