An atomic force microscope (AFM) tip has been used to selectively produce surface enhanced Raman scattering (SERS) for localized Raman spectroscopy. Spectra of thin films, undetectable with a Raman microprobe spectrometer alone, were readily acquired in contact with a suitably gold-coated AFM tip. Similarly, an AFM tip was used to remove sample layers at the nanometer scale and subsequently served as a SERS substrate for ultratrace analysis. This work demonstrates the interface of an AFM with a Raman spectrometer that provides increased sensitivity, selectivity, and spatial resolution over a conventional Raman microprobe. An AFM guiding the SERS effect has the potential for targeted single molecule spectroscopy.
REFERENCES
1.
2.
D. Rugar and P. Hansma, Phys. Today, 23 (1990).
3.
4.
5.
C.
Frisbie
, L.
Rozsnyai
, A.
Noy
, M.
Wrighton
, and C.
Lieber
, Science
265
, 2071
(1994
).6.
7.
A.
Noy
, C.
Frisbie
, L.
Rozsnyai
, M.
Wrighton
, and C. M.
Lieber
, J. Am. Ceram. Soc.
117
, 7943
(1995
).8.
9.
A recent review of NSOM spectroscopy: B. G. Levi, Phys. Today, 18 (1999).
10.
A.
Hammiche
, H. M.
Pollock
, M.
Reading
, M.
Claybourn
, P.
Turner
, and K.
Jewkes
, Appl. Spectrosc.
53
, 810
(1999
).11.
M. S. Anderson, Appl. Spectrosc. 54 (2000).
12.
13.
14.
15.
16.
17.
The silicon tips (TESP) were from Digital Instruments (Santa Barbara, CA) and were coated with a Technics Hummer X argon plasma coater for 120 s, 8 mA, and 1200 V, in 100 mTorr argon with a distance of 5 cm from the target.
18.
The experiments used a 10× objective. The system uses a charge coupled device camera (Photometics Ltd.) and is equipped with a Kaiser holographic notch filter to suppress the Rayleigh scattering. Exposure times were 1 s with ten accumulations co-added.
19.
20.
21.
22.
E. M. Chow, 10th International Conference on Solid-State Sensors and Actuators, Sendai, Japan, 7–10 June, 1999, pp. 1886–1887.
23.
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