Post on 23-Feb-2016
description
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