Tuning the bipolar conductance of an alkali-doped C60 layer sandwiched between two tunneling barriers

Nano Letters

Volumn 5, Issue 1, 2005, Pages 55-59

  Pradhan, Nilay A ^a   Liu, Ning ^a   Silien, Christophe ^a,b   Ho, Wilson ^a  

^a UNIVERSITY OF CALIFORNIA   (United States)

^b UNIVERSITY OF NAMUR   (Belgium)

Author keywords

[No Author keywords available]

Indexed keywords

DOPING (ADDITIVES); ELECTRIC CONDUCTANCE; ELECTRON TUNNELING; FILM GROWTH; MONOLAYERS; RESONANCE; SCANNING TUNNELING MICROSCOPY; SUBSTRATES; TRANSPORT PROPERTIES; TUNING;

BIPOLAR CONDUCTANCE; NEGATIVE SAMPLE BIAS; PARTIAL OXIDATION; TUNNELING BARRIERS;

FULLERENES;

EID: 12844253724     PISSN: 15306984     EISSN: None     Source Type: Journal    
DOI: 10.1021/nl0483744     Document Type: Article

References (24)

1. Lind, E.; Gustafson, B.; Pietzonka, I.; Wernersson, L.-E. Phys. Rev. B 2003, 68, 033312, and references therein.
2. Gryglas, M.; Baj, M.; Chenaud, B.; Jouault, B.; Cavanna, A.; Faini, G. Phys. Rev. B 2004, 69, 165302.
3. Hashizume, T.; Motai, K.; Wang, X.-D.; Shinohara, H.; Saito, Y.; Maruyama, Y.; Ohno, K.; Kawazoe, Y.; Nishina, Y.; Pickering, H. W.; Kuk, Y.; Sakurai, T. Phys. Rev. Lett. 1993, 71, 2959.
4. Grobis, M.; Lu, X.; Crommie, M. F. Phys. Rev. B 2002, 66, 161408.
5. Lu, X.; Grobis, M.; Khoo, K. H.; Louie, S. G.; Crommie, M. F. Phys. Rev. Lett. 2003, 90, 096802.
6. Silien, C.; Pradhan, N. A.; Ho, W.; Thiry, P. A. Phys. Rev. B 2004, 69, 115434.
7. Porath, D.; Levi, Y.; Tarabiah, M.; Millo, O. Phys. Rev. B 1997, 56, 9829.
8. Park, H.; Park, J.; Lim. A. K. L.; Anderson, E. H.; Alivisatos, A. P.; McEuen, P. L. Nature 2000, 407, 57.
9. Park, J.; Pasupathy, A. N.; Goldsmith, J. I.; Chang, C; Yaish, Y.; Petta, J. R.; Rinkoski, M.; Sethna, J. P.; Abruña, H. D.; McEuen, P. L.; Ralph, D. C. Nature 2002, 417, 722.
10. Liang, W. J.; Shores, M. P.; Bockrath, M.; Long, J. R.; Park, H. Nature 2002, 417, 725.
11. Gunnarsson, O. Rev. Mod. Phys. 1997, 69, 575, and references therein.
12. Dresselhaus, M. S.; Dresselhaus, G.; Eklund, P. C. Science of Fullerenes and Carbon Nanotubes; Academic Press: San Diego, 1996.
13. Stipe, B. C.; Rezaei, M. A.; Ho, W. Rev. Sci. Instrum. 1999, 70, 137.
14. Liu, N.; Pradhan, N. A.; Ho, W. J. Chem. Phys. 2004, 120, 11371.
15. Rogero, C.; Pascual, J. I.; Gomez-Herrero, J.; Baro, A. M. J. Chem. Phys. 2002, 116, 832.
16. 60 layer. However, it is unlikely that the Na atom penetrates the fullerene cage under the present experimental conditions. In an observation consistent with those reported here, we found that Li atoms, which are smaller than Na, are also imaged as depressions. See text and ref 23 for more details.
17. z that is important in the data analysis.
18. 60 complex, or the bias exceeds a certain value depending on the alkali species, the atom desorbs, jumps away, or attaches onto the tip.
19. 60 complexes are unstable beyond the range shown in Figure 1, the bias at which peaks L occur cannot be attained. This lack of observation of L, however, does not contradict, but supports the proposed model.
20. 3 thin film.
21. Qiu, X. H.; Nazin, G. V.; Ho, W. Phys. Rev. Lett. 2004, 92, 206102.
22. Silien, C.; Thiry, P. A.; Caudano, Y. Surf. Sci. 2004, 174, 558.
23. 60 lattice constant and radius, respectively. The radius of the cavity thus obtained using the values of a and r given in ref 12 is 2.22 Å. The covalent radii of Na, K, Rb, and Cs are 1.54, 1.96, 2.11, and 2.25 Å, respectively. The corresponding ionic radii are 1.02, 1.38, 1.52, and 1.67 Å (see ref 12).
24. Strictly speaking, the multipole expansion is valid only when the scale of the charge distribution is much smaller than the length scale of the measurement. Since this does not apply in our case, the full charge distribution must be considered for any meaningful predictions. This would require geometric details that cannot be inferred directly from the experiments. However, we anticipate that the electric potential due to the complex will have a dipolar term in the asymptotic limit (due to charge transfer between the alkali atoms and the fullerene molecules).