1. Graphène et BN bientôt inséparables ?
"Le BN sera au graphène ce que le SiO2 est au Si, en mieux !"
Ou encore :
"Si le graphène sert un jour à quelque chose, ce sera grâce au BN !"
(P. Dollfus, 13 octobre 2011)
Institute for Fundamental Electronics, CNRS, University of Paris-Sud, Orsay, France

2. The best : suspended graphene
T = 5 K
SiO2 substrate: µmax = cm2/Vs
Suspended: µmax = cm2/Vs

3. But,…  However, suspended graphene is not suitable for applications
Need for insulating substrate
 Standardly used substrate: SiO2
- Compatible with standard processing facilities 
- Many problems or limitations (mobility): 
- surface roughness
- scattering by charged surface states and impurities
 Epitaxial Graphene on SiC
- Mobility not better than for G reported on SiO2
- Thickness (number of layers) difficult to control
- Poor uniformity
- Possibility of bandgap ?? (controversy)

4. The advantages of h-BN substrates
 The future of graphene: h-BN substrate
Xue, Nature Mat. 2011
Same lattice structure, very small lattice mismatch (1.7%)
- Free of dangling bonds and surface charge traps
- Smooth surface
- EG (BN) = 5.97 eV
Giovanetti, PRB 2007
(+ bandgap opening in graphene: 53 meV)

5. The advantages of h-BN substrates
Monolayer: µ = cm2/Vs (electrons) and
Bilayer: µ = cm2/Vs (electrons) and cm2/Vs (holes)
EG  0

6. Avoiding mechanical transfer ? Yes !
et al.
Et ça marche…

7. Avoiding mechanical transfer ? Yes
 h-BN as gate insulator (even double-gate ?)

8. Graphene / h-BN stacks
(other information in Zhao Physica E 43 (2010) 440

9. Towards graphene/h-BN heterostructures

10. Graphene/h-BN heterostructures

11. Graphene/h-BN heterostructures

12. Future works ?
By means of tight-binding description of the full device
 Graphene transistors with single or double BN gate
 RTD in in-plane G-BN-G-BN-G structures
Alternative to: - nanostructuration of GNRs with different sections
- doping to generate barriers