7.01 Roll-To-Roll Graphene Transfer microsystems technology laboratories Marek Hempel, Jing Kong, Tomas Palacios, [email protected] Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology Transferring CVD Graphene onto Flexible Substrates by Hot Lamination and Electrochemical Delamination 1. Goal and Applications: Use graphene to make flexible, conductive and transparent electrodes • Needed for optoelectronic and wearable applications, for example: 2. Background: • Graphene is nearly transparent, ultra strong and has an extremely high carrier mobility • This makes it a promising material to use as transparent conductive electrodes • Large areas can only be synthesized by chemical vapor deposition (CVD) on Cu foil 8. Acknowledgement: This project was funded by eni-MIT Solar Frontiers Center. 3. Approach: • Use pressure and heat to laminate graphene to target • Separate by hydrogen bubbles (use electrolysis) 5. Metrology: • Molding of copper foil texture highly visible on EVA • Dark field microscopy (DF) helps to visualize features Touch Screens Smart Windows Solar Cells Displays Challenge is to transfer graphene in a scalable way and with high quality 4. Implementation: Lamination • Use EVA coated PET as substrate • Temp. range of heat shoes: 90°– 250°C • Speed range of DC motors: 0.7 – 5 mm/s • Roller pressure ranges from: 0 – 400 N Delamination • Use sodium chloride (NaCl) or sodium hydroxide (NaOH) as electrolyte with 0.5 mol/l Hot lamination Electrochemical Delamination 6. Electrical Characterization and Doping 7. Repeated Lamination and Delamination DF 100x 477.1 175.7 4568.3 761.1 0 1000 2000 3000 4000 5000 G on SiO2 G on SiO2 doped G on PET/EVA G on PET/EVA doped avg. sheet resistance [Ω/□] 1E+11 1E+12 1E+13 1E+14 200 2000 Carrier concentration [cm -2 ] mobility [cm 2 /Vs] 1L 1L doped 2L 2L doped 10000 10μm 1E+11 1E+12 1E+13 1E+14 200 2000 Carrier concentration [cm -2 ] mobility [cm 2 /Vs] G on SiO2 G on PET/EVA G on SiO2 doped G on EVA/PET dopted 10000 1L 1L doped 2L 2L doped sheet resistance [kΩ/□] 6.0x 4.9x 3.4x 6 5 4 3 2 1 0 • Stacking 2 graphene layers improves conductivity by 3.4x • This is more than expected increase of factor of 2x All rights reserved by Hempel, et al. Reproduced here with permission for educational purposes only.
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7.01 Roll-To-Roll Graphene Transfer
microsystems technology laboratories
Marek Hempel, Jing Kong, Tomas Palacios, [email protected]
Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology
Transferring CVD Graphene onto Flexible Substrates by
Hot Lamination and Electrochemical Delamination
1. Goal and Applications:
Use graphene to make flexible, conductive and transparent electrodes
• Needed for optoelectronic and wearable applications, for example:
2. Background:
• Graphene is nearly transparent, ultra strong
and has an extremely high carrier mobility
• This makes it a promising material to use as
transparent conductive electrodes
• Large areas can only be synthesized by
chemical vapor deposition (CVD) on Cu foil
8. Acknowledgement:
This project was funded by eni-MIT Solar Frontiers Center.
3. Approach:
• Use pressure and heat to
laminate graphene to target
• Separate by hydrogen
bubbles (use electrolysis)
5. Metrology:
• Molding of copper foil texture
highly visible on EVA
• Dark field microscopy (DF)
helps to visualize features
Touch ScreensSmart Windows Solar Cells Displays
Challenge is to transfer graphene in a scalable way and with high quality
4. Implementation:
Lamination
• Use EVA coated PET as substrate
• Temp. range of heat shoes: 90°– 250°C
• Speed range of DC motors: 0.7 – 5 mm/s
• Roller pressure ranges from: 0 – 400 N
Delamination
• Use sodium chloride (NaCl) or sodium
hydroxide (NaOH) as electrolyte with 0.5 mol/l
Hot laminationElectrochemical
Delamination
6. Electrical Characterization and Doping
7. Repeated Lamination and Delamination
DF 100x
477.1175.7
4568.3
761.1
0
1000
2000
3000
4000
5000
G on SiO2 G on SiO2doped
G onPET/EVA
G onPET/EVA
doped
avg
. sh
eet
resis
tan
ce [Ω
/□]
1E+11
1E+12
1E+13
1E+14
200 2000Carr
ier
co
ncen
trati
on
[cm
-2]
mobility [cm2/Vs]
1L 1L doped
2L 2L doped
10000
10µm
1E+11
1E+12
1E+13
1E+14
200 2000
Carr
ier
co
ncen
trati
on
[cm
-2]
mobility [cm2/Vs]
G on SiO2G on PET/EVAG on SiO2 dopedG on EVA/PET dopted
10000
1L 1L
doped
2L 2L
doped
sh
eet
resis
tan
ce [
kΩ
/□]
6.0x
4.9x
3.4x
6
5
4
3
2
1
0
• Stacking 2 graphene
layers improves
conductivity by 3.4x
• This is more than
expected increase of
factor of 2x
All rights reserved by Hempel, et al. Reproduced here with permission for educational purposes only.
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