1. 라만 의 원리와 그의 응용 (Normal,SERS,TERS)
군산대학교 화학과
유수창
기초과학지원연구원,
Kunsan National University, Department of Chemistry, Raman Spectroscopy Lab.

2. Raman and Fraud

4. Raman vs Infrared Spectra
McCreery, R. L., Raman Spectroscopy for Chemical Analysis, 3rd ed., Wiley, New York: 2000

8. Presentation of Raman Spectra
lex = 1064 nm = 9399 cm-1
Breathing mode:
9399 – 992 = 8407 cm-1
Stretching mode:
9399 – 3063 = 6336 cm-1

10. Resonance Raman
Raman signal intensities can be enhanced by resonance by factor of up to 105 => Detection limits 10-6 to 10-8 M.
Typically requires tunable laser as light source.

11. Resonance Raman Spectra
lex = nm
lex = nm
lex = 1014 nm

12. Fluorescence Background in Raman Scattering
McCreery, R. L., Raman Spectroscopy for Chemical Analysis, 3rd ed., Wiley, New York: 2000

13. Applications of Raman Spectroscopy
Identification of phases (mineral inclusions, composition of the gas phase inclusions)
Anions in the fluid phase (OH-, HS-, etc.)
Identification of crystalline polymorphs (Sillimanite, Kyanite, andalusite, etc.)
Measurement of mid-range order of solids
Measurement of stress
High-pressure and High-temperature in situ studies
Phase transition and order-disorder transitions in minerals (quartz, graphite)
Water content of silicate glasses and minerals
Speciation of water in glasses
To visit caltech webpage: mineral.gps.caltech.edu Mineral Spectroscopy Server.

14. Raman Instrumentation

16. Dispersive and FT-Raman Spectrometry
McCreery, R. L., Raman Spectroscopy for Chemical Analysis, 3rd ed., Wiley, New York: 2000

18. Extremely high spectral resolution by Echelle grating
Actual pixels of CCD camera are plotted
Spectral resolution: /cm (per pixel) for 473 nm laser
For 785 nm laser spectra resolution would be even higher: 0.1 1/cm per pixel
Measurement parameters
Laser: 473 nm
Objective: 100x, 0.95 NA
Grating: Echelle !
CCD pixels H shift speed: 32
Exposure time: 1 sec
Number of exposures: 15
Si line, 1st order

19. AFM with 100x 0.7 NA objective in upright configuration –
for non-transparent samples
Laser deflectometer
objective
Imaging optics
CCD video camera
AFM probe
Sample
XYZ scanner
Excitation light
Scattered light
Beam splitter 2
Beam splitter 1
Probe deflectometer
Optical AFM head
(100x,0.7 NA objective inside)
Laser input&scanning module
NA=0.7
400 nm resolution
NTEGRA Spectra 19

20. Combination of AFM with Raman
NTEGRA Spectra
One object – many techniques
Atomic-force microscopy:
mechanical, electrical, magnetic properties and nanomanipulations
Confocal Raman: imaging and spectroscopy
Near-field optical microscopy
Confocal fluorescence: imaging and spectroscopy
Conventional microscopy and reflected laser confocal imaging
Tip Enhanced Raman and Fluorescence microscopy
Measurements both in air and liquid
NTEGRA Spectra
NTEGRA Spectra 20

21. center of mass position
Si nanowire
Raman map (main Si band)
Optical image
Stressed Si
Pristine Si
_____ 5 µm
_____ 5 µm
Raman map, Si band
center of mass position
AFM topography
_____ 5 µm
_____ 5 µm
Fluorescence map
Raman map
(stressed Si band)
_____ 5 µm
NT-MDT NTEGRA Spectra + Renishaw Raman microscope

22. Chemical composition mapping
AFM image, Raman spectra and Raman images of single-walled carbon nanotubes. Amorphous carbon is visualized in D-band (1351 cm-1) while well structured nanotubes are present in RBM- band (173 cm-1). Raman images size 5x5 μm.
Images courtesy of Dr.Kudryashov, TII, Tokyo, Japan.
NTEGRA Spectra 22

23. Graphene flakes: AFM & Raman microscopy
70x70 µm
4 layers
3 layers
70x70 µm
2 layers
Optical image
70x70 µm
4 layers
3 layers
2 layers
1 layer
AFM topography
1 layer
2D band center of mass
NTEGRA Spectra
Data measured: P.Dorozhkin & E. Kuznetsov, NT-MDT 23

24. Double resonant Raman scattering –
Raman spectroscopy of graphene flakes
From: Davy Graph et al., 2006
G-band
2D-band
2D band center of mass
4 layers
3 layers
G-band intensity
2 layers
Double resonant Raman scattering –
origin of 2D peak
1 layer
NTEGRA Spectra
Data measured: P.Dorozhkin & E. Kuznetsov, NT-MDT

25. Polymer blend 40x40 µm scans AFM topography AFM phase
Confocal laser image
Raman map (line A – next slide)
NTEGRA Spectra
Data measured: P. Dorozhkin, NT-MDT 25

26. Raman spectra and intensity maps of 2 characteristic lines
Polymer blend
Raman spectra and intensity maps of 2 characteristic lines
Line B
Line A
Line A
40x40 µm scans
Line B
NTEGRA Spectra
Data measured: P. Dorozhkin, NT-MDT 26

27. Raman Spectroscopy of Graphite

30. Probing Single Molecules and Single Nanoparticles
by Surface-Enhanced RAMAN Scattering
SHUMING NIE * and Steven R. Emory
Science 21 February 1997: Vol no. 5303, pp

31. Figure 2. Tapping-mode AFM images of screened Ag nanoparticles.
(A) Large area survey image showing four single nanoparticles.
Particles 1 and 2 were highly efficient for Raman enhancement, but particles 3 and 4 (smaller in size) were not.
(B) Close-up image of a hot aggregate containing four linearly arranged particles.
(C) Close-up image of a rod-shaped hot particle. (D) Close-up image of a faceted hot particle.

32. Figure 3. Surface-enhanced Raman spectra of R6G obtained with a linearly polarized confocal laser beam from two Ag nanoparticles.
The R6G concentration was 2 ×  M, corresponding to an average of 0.1 analyte molecule per particle. The direction of laser polarization and the expected particle orientation are shown schematically for each spectrum. Laser wavelength, 514.5 nm; laser power, 250 nW; laser focal radius, ~250 nm; integration time, 30 s. All spectra were plotted on the same intensity scale in arbitrary units of the CCD detector readout signal.

33. Figure 6. Direct comparison of laser-induced fluorescence and SERS of a single R6G molecule. Note that single-molecule fluorescence signals were observed as diffraction-limited spots (~500 nm in diameter or 6 pixels). The integrated Raman signal appeared much larger in size, but its full width at half maximum was similar to that for fluorescence. Detailed signal intensities and widths are shown for lines (A) and (B). Laser wavelength, 514.5 nm; excitation power, 10 mW; integration time, 5 s.

34. Tip Enhanced Raman Scattering
A route to Raman microscopy with subwavelength spatial resolution and single molecule sensitivity
TERS – “inverted” SERS effect (scanning metal tip is a HOT SPOT)
Metal AFM probe
Enhanced Raman signal
200 nm
Electromagnetic field intensity around metal tip
Focused laser spot
NTEGRA Spectra 34

35. UPRIGHT geometry (non-transparent samples)
Tip Enhanced Raman
UPRIGHT geometry (non-transparent samples)
TERS collection E
TERS excitation 35

36. TERS- A sensitive Surface Probe

37. Tip Enhanced Raman Scattering

39. TERS – SSC in Air

40. TERS: Carbon deposited on YSZ

41. 감사합니다.