1. Niels Bohr Institute, Nano-Science Center, University of Copenhagen
Isaac Newton Institute Workshop, Cambridge September 2004
Field Effect Transistor Behaviour in Single Wall Carbon Nanotubes and Peapods
Poul Erik Lindelof
Niels Bohr Institute, Nano-Science Center, University of Copenhagen
18-Sep-18
Niels Bohr Institute

2. Field Effect Transistor Behaviour in Single Wall Carbon Nanotubes and Peapods Poul Erik Lindelof Niels Bohr Institute, Nano-Science Center, University of Copenhagen
Henrik Ingerslev Jørgensen, PhD student
Jonas Rahlf Hauptmann, PhD-student
Thomas Sand Jespersen, PhD-student
Kasper Grove-Rasmussen, Ph.D.-student (p.t. visiting NTT BRL, Japan)
Ane Jensen, Dr
Jesper Nygård, Dr
& collaboration with Andrei Khlobystov, Oxford University
18-Sep-18
Niels Bohr Institute

3. Field Effect Transistor Behaviour in Single Wall Carbon Nanotubes and Peapods
Outline of talk:
Importance of contacts,
Coulomb blockade, odd-even effects due to spin
Zeeman splitting, ESR?
Kondo effect
Hybrids with GaAs
Magnetic contacts
Peapods, Periodic modulation
Summary
Notes may be nice
18-Sep-18
Niels Bohr Institute

4. 3 carbon nanotubes (10,10) (15,0) (12,8) 18-Sep-18
(10,10) (15,0) (12,8)
18-Sep-18
Niels Bohr Institute

5. TEM of carbon nanotube robe
A nanotube (or two?)
TEM picture
20 nm
18-Sep-18
Niels Bohr Institute

6. Assignment by Raman spectra
Thomas Sand Jespersen, MSc thesis
18-Sep-18
Niels Bohr Institute

7. Contact configuration
although carbon atoms only!
Contact configuration
2-point Electrical Resistance
drain
Au/Ti contacts
Carbon nanotube
Silicondioxide (300 nm)
Highly doped silicon
source
gate
18-Sep-18
Niels Bohr Institute

8. Contacting a SWCNT
10µm
50µm
18-Sep-18
Niels Bohr Institute

9. SWCNT, metals or semiconductors
18-Sep-18
Niels Bohr Institute

10. 3 examples of Contact resistances
G300K = 0.3 e2/h
G300K = 1.8 e2/h
G300K = 3 e2/h
It is ThreeTypesGVg.OPJ, originally made for the Kondo paper
Devices: cdot, yin, metallicA
T = 1K
T = 100mK
Theoretical maximum
Gmax = 4 e2/h
18-Sep-18
Niels Bohr Institute

11. Metallic SWCNT, Temperature Dependence
P.E. Lindelof, et al., Physica Scripta T02, 22 (2002)
18-Sep-18
Niels Bohr Institute

12. Odd-Even Additional energies
D.H. Cobden and J. Nygård Phys,Rev,Lett. 89, (2002)
18-Sep-18
Niels Bohr Institute

13. Bias Spectroscopy, Zeeman splitting
P.E. Lindelof , et al., Physica Scripta T02, 22 (2002)
18-Sep-18
Niels Bohr Institute

14. Wolfgang Pauli and Niels Bohr 1951, looking at a spinning object!
18-Sep-18
Niels Bohr Institute

15. Kondo bias spectroscopyQ E O D eV
J. Nygård et al., Nature 408,342 (2000)
18-Sep-18
Niels Bohr Institute

16. Kondo temperature a b c J. Nygård et al., Nature 408, 342 (2000)
G0 (e2/h) TK (K) a b c
Fig 2 abc from modified Fig2FatCompilation.OPJ
Fig 2mega meg56Fat1_v2cut.hdf, meg56Fat2_cut.hdf
Fig 2 IV white_I-V_and_FWHMs.OPJ
J. Nygård et al., Nature 408, 342 (2000)
18-Sep-18
Niels Bohr Institute

17. Carbon nanotube inside a MBE GaAlAs single crystall= +
A. Jensen, J.Hauptmann, J, Nygård, J. Sadowski, P.E. Lindelof, Nano Letters (2004)
18-Sep-18
Niels Bohr Institute

18. Device fabrication MBE chamber MBE grown substrate:
- n-doped GaAs
- insulating superlattice barrier
- amorphous As cap (protection)
Dispersion of single-wall
nanotubes from suspension,
ambient conditions
18-Sep-18
Niels Bohr Institute

19. Device fabrication MBE chamber
Epitaxal overgrowth with Ga0.95Mn0.05As by MBE at 250 C
Result: nanotubes incorporated in GaAs sandwich
Reloaded in the MBE chamber
Desorption of As cap at 400 C,
leaving the nanotubes on the
clean GaAs crystal surface
18-Sep-18
Niels Bohr Institute

20. Mesa, Trench etch, SWCNTs
Trench and SWCNT
18-Sep-18
Niels Bohr Institute

21. Device architecture a) b) 7 5 4 6 3 2 1 Au/Zn (Ga,Mn)As SWNT Cr/Au
x100 2
AlAs 1
GaAs
18-Sep-18
Niels Bohr Institute

22. Configurations in various magnetic fields
18-Sep-18
Niels Bohr Institute

23. AFM scan of SWCNT between MBE grown GaAs electrodes
Single wall carbon nanotube
GaAs
The trench is 0.5 µm wide
18-Sep-18
Niels Bohr Institute

24. G(Vg,B) for GaMnAs-SWCNT-GaMnAs
18-Sep-18
Niels Bohr Institute

25. G(Vsd,B,T) for GaMnAs-SWCNT-GaMnAs
18-Sep-18
Niels Bohr Institute

26. Magnetoresistance of GaMnAs-SWCNT-Au
18-Sep-18
Niels Bohr Institute

27. Juliere’s model G(++)~n(1,+)n(2,+)+n(1,-)n(2,-)
P(1)=[n(1,+)-n(1,-)]/[n(1,+)+n(1,-)]
DG/G=[G(++)-G(+ -)]/G(++)
=2P(1)P(2)/[1+P(1)P(2)] >0 Negative magnetoresistance
18-Sep-18
Niels Bohr Institute

28. Tunnelling into two domains (Streda, unpublished)Tt
T(1,+)
T(2,-)= T(2,-)
T(1,+)=pT1, T(1,-)=(1-p)T1, T(2,+)=T(2,-)=T2
G(p=1)=G(+)+G(-)=T1TtT2/[Tt(T1+T2)+2T1T2]
G(p=1)-G(p=½)= -G(p=1)[T1/T2 + 2T1/Tt] magnetoresistance>0
18-Sep-18
Niels Bohr Institute

29. C-60@SWCNT Peapod K. Haldrup, A.N. Khlobystov et al. 18-Sep-18
Niels Bohr Institute

30. Raman spectra a) SWCNT b) SWCNT - through treatment
c) Peapod
18-Sep-18
Niels Bohr Institute

31. Peapod Conductance vs. Vg
18-Sep-18
Niels Bohr Institute

32. G(290) vs. power law exponent. C-60@SWCNT (O) & SWCNT (l)
Haldrup, Khlobystov et al., To be published
18-Sep-18
Niels Bohr Institute

33. Nanometer periodic modulation of potential along SWCNT
Thomas Sand Jespersen, Poul Erik Lindelof, unpublished
18-Sep-18
Niels Bohr Institute

34. MBE growth of SL with guiding structures. Cleaved Edge Overgrowth
18-Sep-18
Niels Bohr Institute

35. AFM picture of cleaved and etched surface
18-Sep-18
Niels Bohr Institute

36. AFM study of 30 nm period superlattice on the cleaved edge
18-Sep-18
Niels Bohr Institute

37. Carbon nanotube decoration of CEO SL surface
18-Sep-18
Niels Bohr Institute

38. SWCNT superlattice Raman spectrum. No data for the combination yet.
18-Sep-18
Niels Bohr Institute

39. Summary The contact resistance to metallic carbon nanotubes,
Temperature dependence of electrical conductance
Odd-even Coulomb blockade conductance peaks
Zeeman splitting (g=2)
Spin ½ co-tunneling (Kondo effect)
GaAs-CNT hybrids, magnetic contacts
Peapods, CEO periodic modulation
18-Sep-18
Niels Bohr Institute

40. Movie of ”spinning object”
18-Sep-18
Niels Bohr Institute

41. The ”spinning object” in action
18-Sep-18
Niels Bohr Institute