Infrared Absorption Enhancement of C 60 by Overlaying Thin Silver Island Films

Abstract

Normal-incidence infrared absorption has been observed for silver overlaid C₆₀ thin films formed on surface-oxidized Si(111) substrates as a function of the silver or C₆₀ film thickness. The absorption spectra exhibit bands at 1429 and 1180 cm⁻¹ due, respectively, to the infrared active T_1u (4) and T_1u (3) modes of C₆₀ in multi-layers. Additionally, two bands appear at 1442 and 1370 cm⁻¹. The former band is caused by activation of the infrared inactive (Raman active) A_g (2) mode via electron transfer from the silver to adsorbed C₆₀, and the latter is assigned to the T_1u (4) mode red-shifted by the charge transfer. These bands are all enhanced in intensity dependent either upon the silver or C₆₀ thickness, i.e., the largest absorption enhancement is obtained for 25-monolayers-thick silver and 12-nm-thick C₆₀. Under atomic force microprobe inspection, the average size and height of the islands in the overlaid 25-monolayers-thick silver change with underlying C₆₀ film thickness. The influence of the C₆₀ film structure upon the silver film and in turn the absorption intensity is strongly suggested.

Keywords

Silver Surface-enhanced infrared absorption Atomic force microscopy AFM

Get full access to this article

View all access options for this article.

References

Krätschmer

Lamb

L. D.

Fostiropoulos

and Huffman

D. R

, Nature (London) 347, 354 (1990).

Weckesser

Cepek

Fasel

Barth

J. V.

Baumberger

Greber

and Kern

, J. Chem. Phys. 115, 9001 (2001).

Kuzmany

Winkler

and Pichler

, J. Phys.: Condens. Matter 7, 6601 (1995).

Manaila

Belu-Marian

Macovei

Brehm

Marian

D. Th.

and Baltog

, J. Raman Spectrosc. 30, 1019 (1999), and references therein.

Caudano

Peremans

Thiry

P. A.

Dumas

and Tadjeddine

, Surf. Sci. 368, 337 (1996).

Peremans

Caudano

Thiry

P. A.

Dumas

Zhang

W. Q.

Le Rille

and Tadjeddine

, Phys. Rev. Lett. 78, 2999 (1997).

Dumas

Hein

Otto

Persson

B. N. J.

Rudolf

Raval

and Williams

G. P

, Surf. Sci. 433–435, 797 (1999).

Silien

Caudano

Peremans

and Thiry

P. A

, Appl. Surf. Sci. 162–163, 445 (2000).

Swami

and Koel

B. E

, Thin Solid Films 348, 30 (1999).

10.

Surface Enhanced Raman Scattering, Chang

R. K.

and Furtak

T. E

, Eds. (Plenum Press, New York, 1982).

11.

Otto

, “Electronic Scattering, Spin Effects, SERS, and Morphic Effects”, in Light Scattering in Solids IV, Cardona

and Güntherodt

, Eds. (Springer, Berlin, 1983), p. 289.

12.

Hartstein

Kirtley

J. R.

and Tsang

J. C

, Phys. Rev. Lett. 45, 201 (1980).

13.

Hatta

Ohshima

and Suëtaka

, Appl. Phys. A 29, 71 (1982).

14.

Hatta

Suzuki

and Suëtaka

, Appl. Phys. A 35, 135 (1984).

15.

Osawa

, Bull. Chem. Soc. Jpn. 70, 2861 (1997), and references therein.

16.

Wadayama

Suzuki

and Hatta

, Appl. Phys. A 64, 501 (1997).

17.

Suzuki

Seki

Inamura

Tanabe

Wadayama

and Hatta

, Surf. Sci. 427–428, 136 (1999).

18.

Wadayama

Suzuki

Takeuchi

Seki

Tanabe

Suzuki

and Hatta

, Appl. Phys. A 69, 77 (1999).

19.

Suzuki

Seki

Inamura

Tanabe

Wadayama

and Hatta

, Surf. Sci. 433–435, 261 (1999).

20.

Bjerke

A. E.

and Griffiths

P. G

, Appl. Spectrosc. 56, 1275 (2002).

21.

Wadayama

Takada

and Hatta

, Appl. Phys. A, paper in press (2003).

22.

Seki

Takada

Tanabe

Wadayama

and Hatta

, Surf. Sci. 506, 23 (2002).

23.

Priebe

Fahsold

Geyer

and Pucci

, Surf. Sci. 502–503, 388 (2002).

24.

Zheng

S.-G.

Sun

S.-G.

and Chen

S.-P

, J. Appl. Chem. 31, 749 (2001).

25.

Suzuki

Sagisaka

and Hatta

, Appl. Surf. Sci. 84, 1 (1995).

26.

Wadayama

Takada

Sugiyama

and Hatta

, Phys. Rev. B 66, 193401 (2002).

27.

Hatta

Suzuki

and Suëtaka

, Appl. Surf. Sci. 37, 299 (1989).

28.

Badilescu

Ashrit

P. V.

and Truong

V.-V

, Appl. Phys. Lett. 52, 1551 (1988).

29.

Sigarev

A. A.

and Yakovlev

V. A

, Opt. Spectrosc. (USSR) 56, 336 (1984).

30.

Badliescu

Ashrit

P. V.

Girouard

F. E.

and Truong

V.-V

, J. Electrochem. Soc. 136, 3599 (1989).

31.

Tanabe

Shibahara

Buckmaster

Ishibashi

Wadayama

and Hatta

, Surf. Sci. 466, 1 (2000).

32.

Weeks

and Hater

W. G

, J. Chem. Phys. 90, 4744 (1989).

33.

Stanton

R. E.

and Newton

M. D

, J. Phys. Chem. 92, 2141 (1988).

34.

Cyvin

S. J.

Brendsdal

Cyvin

B. N.

and Brunvoll

, Chem. Phys. Lett. 143, 377 (1988).

35.

Chase

Herron

and Holler

, J. Phys. Chem. 96, 4262 (1992).

36.

Caudano

Peremans

Thiry

P. A.

Dumas

and Tadjeddine

, Surf. Sci. 377–379, 1071 (1997).

37.

Suzuki

Kobayashi

Hatta

and Otto

, Jpn. J. Appl. Phys. 36, 4446 (1997).

38.

Krauth

Fahsold

and Pucci

, J. Chem. Phys. 110, 3113 (1999).