AFM â€“ Confocal Raman â€“ SNOM and Tip Enhanced Raman ...

AFM – Confocal Raman – SNOM and Tip Enhanced Raman : 

Instrumentation and Applications 

Outlook: 

11. Introduction to NT NT-MDT MDT 

2. AFM – Confocal Raman – SNOM – 

TERS iinstrumentation t t ti 

3. AFM & “micro”- Raman studies: 

Graphene, nanowires, nanotubes, 

polymers, bio-objects etc. 

4. Tip Enhanced Raman Scattering: 

“nano – Raman” imaging 

5. Scanning Near Field Optical 

Microscopy (SNOM) 

www.ntmdt.com/device/ntegra-spectra 

Contact: Contact : Dr. Pavel Dorozhkin, dorozhkin@ntmdt.com

NT-MDT NT MDT Europe 

Eindhoven, NL 

NT-MDT America 

SSanta t Clara, Cl USA 

NT-MDT Basic offices modes worldwide 

www.ntmdt.com 

NT-MDT Head Office, 

Moscow, Russia 

Distributors 

Sales Representatives 

NT-MDT Shanghai 

Shanghai, China 

NT-MDT S&L 

Limerick Limerick, Ireland

NT-MDT Product line 

NANOFABs N NO s 

NanoLabs 

Ed Educations ti 

Accessories 

• More than 20 years on the SPM/AFM market 

y 

• More than 2400 SPM installations Worldwide 

• Offices: Moscow, Eindhoven, Limerick, San-Francisco, Shanghai

SPM modes: 

AFM (contact, intermittent contact), STM

ALL major AFM modes are integrated with RAMAN 

NT-MDT Standard Measuring modes 

More than 30 possible different AFM modes 

INTEGRATED with Raman-Confocal 

• STM 

• Contact AFM 

• Lateral Force Microscopy 

• Resonant Mode -Semicontact 

• Noncontact AFM mode 

• Phase Imaging 

• Force Modulation (viscoelastisity) 

• Magnetic force Microcopy 

• Electrostatic Force Microscopy 

• Adhesion Force Imaging 

• AFM Lithography-Force 

• Spreading Resistance Imaging (SRI) in Currents 30fA-50nA 

• AFM Nanolitogrphy (voltage and scratching) 

• SScanning Capacitance C Imaging (SC (SCI) ) ( (dC/dZ, C/ dC/dV) C/ ) 

• Scanning Kelvin probe microscopy (SKM) 

• Force distance curves 

• Force Volume 

• NNanomanipulation i l ti 

• Piezoresponce Mode 

• Sample heating for in-situ melting 

• I/V spectroscopy, I(Z) spectroscopy etc. 

• El Electrochemistry 

t h i t 

• SNOM 

• …. 

SPM PROBES: 

- AFM cantilever (any type) 

- STM 

- tuning fork (shear force) 

- tuning fork (normal force)

Inverted 

UUpright i ht

SNOM 

ONE SPM BASEMENT & CONTROLLER – 

DIFFERENT INSTRUMENTS 

AFM + STM 

NT-MDT SPM’s abilities 

AFM - Confocal Raman - 

SNOM (UPRIGHT) 

AFM - Confocal Raman - SNOM (INVERTED)

NTEGRA Spectra 

Inverted microscope setup (for transparent samples) 

“AFM + SNOM + 3D confocal Raman microscope + TERS” system 

Lasers 

NTEGRA universal 

SPM platform 

Inverted microscope 

(Olympus (Olympus, Nikon …) 

) 


AFM-head 

Raman unit (NT-MDT) (NT MDT) 

Sample scanning stage 

(100x,1.4 NA objective inside)

NTEGRA Spectra in Upright setup 

“AFM + SNOM + 3D confocal Raman microscope + TERS” 

system for non-transparent samples 


Raman unit (Renishaw) 

Optical AFM-head 

with integrated 100x objective 

Sample scanner 

NTEGRA universal 

SPM platform

Combination of AFM with Raman 

Confocal 

Raman: 

imaging and 

spectroscopy 

Confocal 

fluorescence: 

iimaging i and d 

spectroscopy 


One object j – many y techniques q 

Atomic-force 

microscopy: 

mechanical, 

electrical, magnetic 

properties p p and 

nanomanipulations 

Tip Enhanced Raman and 

Fluorescence microscopy 

Near-field 

optical 

microscopy i 

Optical (white light) 

microscopy and 

reflected laser 

confocal imaging 

Measurements in air, in liquid or in a controlled environment 


NTEGRA Spectra



Confocal Raman/Fluorescence - critical resolution

Resolution test: features 200 nm apart are clearly resolved 

Raman map measurement parameters: 

Objective: 100x, oil immersion 

Laser: 473 nm, Grating: 150 lines/mm 

Exposure time 0.3 sec 

Spectra per sec: >3 

PPoint i t number: b 200 200x200 200 pix 

i 

Sample: p Mineralic toothpaste p 

Resolution: < 200 nm 

Line #1, Integral intensity 

200 nm 

300 nm

Very high spectral resolution by Echelle grating 

Measurement parameters 

Laser: 473 nm 

Objective: 100x, 0.95 NA 

Grating: Echelle 

Actual pixels p of CCD camera are plotted p 

(26 µm pixel size) 

Spectral resolution: 

0281/cm(pixel 0.28 1/cm (pixel to pixel) for 473 nm laser 

0.11 1/cm (pixel to pixel) for 785 nm laser 

Si line, 1 st order

3D Raman mapping, Polystyrene microspheres 

X,Y - resolution: 200 nm 

Z – resolution: 500 nm 

10100 

1/cm 

3D Raman image 

XY cross-section 

scan size 10x10x14 µm µ


Upright configuration for AFM – Confocal Raman – TERS 

U i i t ti fAFM ith 

Unique integration of AFM with 

high resolution optical microscopy and spectroscopy

AFM with 100x 0.7 NA objective in upright configuration – 

for non-transparent samples 

Laser 

input&scanning 

module d l 


Probe 

deflectometer 

Optical AFM head 

(100x,0.7 NA 

objective inside) 

CCD video camera 

Imaging optics 

Beam splitter p 2 

Beam splitter 1 

AFM probe 

XYZ scanner 

NA=0.7 

400 nm resolution 

Excitation light 

Scattered light 

Laser 

deflectometer 

Sample 

objective

AFM cantilever under 100x objective (in upright geometry) 

Cantilever 

AFM Optical Image 

1 µm height letters are 

readable – thanks to 

100x objective 

(see next slide for AFM) 

Black spot at the apex of 

cantilever is the exact 

point there the tip 

touches substrate !!! 

AFM probe over a structured Si substrate. 

View through 0.7N 100x objective, resolution 400 nm 

Apex of opaque Si tip looks transparent on the image 

This unique observation is due to high aperture (0.7 NA) of the imaging objective 

NTEGRA Spectra


AFM – Confocal Raman “classical applications” 

Stress in Silicon 

Sili Silicon nanowires i 

Carbon nanotubes 

GGraphene h 

Bio objects 

…

Mapping stress in Si by spectral shift of 520 cm -1 line 

Stress distribution around nanoindentation in Silicon substrate 

AFM topography of indentation in 

silicon substrate 

σ(MPa) = -435 ∆ω (1/cm) 


Scan size: s 12xx12 

microon 

0.5 1/ cm 

Center of mass position shift of 520 1/cm silicon 

line – proportional to stress distribution around 

the indentation. 

Spectral resolution: better then 0.1 1/cm

Si nanowire – snapshot from the experiment 

cantilever apex 

cantilever cantilever 

nanowire 

nanowire laser spot 

NTEGRA Spectra + Renishaw Raman microscope

Si nanowire - comprehensive characterization in one 

sample p scan 

Optical image 

AFM topography 

Raman map (main Si band) 

_____ 5 µm _____ 5 µm 

Raman map, Si band 

center of mass position 

_____ 5 µm _____ 5 µm 

Fluorescence map Raman map 

(Si nanoparticles band) 

_____ 5 µm 

Stressed Si 

Pristine Si 

Si nanoparticles 

NT-MDT NTEGRA Spectra + Renishaw Raman microscope

Sample: SWCNs, Raman spectrum of nanotube bundle 

Grating: 600 lines/mm 

RBM D 


G + 

G - 

Laser: 473 nm 

2D

Intensity distribution of different Raman bands & 

AFM topography image of individual NT bundle 

RBM-band D-band G - - band G + - band 

AFM height g AFM phase 

Integration time: 100 ms / point. 50*150 points. 

Total spectrum was acquired at each point of the scan. After measurement, different Raman 

bands are chosen and their intensity distribution is analyzed. All the images (AFM + all Raman 

maps) can obtained simultaneously, simultaneously in a single experiment experiment, without any moving of the sample 

or objective 

NTEGRA Spectra

2 nm 

Sensing individual SWNTs on Si substrate 

Spectral integration time at 1 point : 100 msec 

E (Horizontal pol.) 

E (vertical pol.) 

Topography Raman map (G-band)

NTEGRA Spectra p 

AFM – Confocal Raman of Graphene

Lateral Force Microscopy 

Graphene, AFM + Confocal Raman 

One experiment - multiple data 

Electrostatic Force 

Force Modulation Microscopy 

Microscopy 

Capacitance 

Microscopy 

Raman Map, Mass Center of 

2D (G’) Band 

AFM Topography, Size: 30*30 µm 

Scanning Kelvin Probe 

Microscopy 

RRaman MMap, GG-band b d 

Intensity 

Confocal Rayleigh 

Microscopy 

Data from: E. Kuznetsov, 

S. Timofeev, P. Dorozhkin, NT-MDT Co.

HIGH RESOLUTION AFM & STM 

The high-resolution AFM image showing 

an assembly of single-layer, 

functionalized Graphene sheets sheets. 

Some of the sheets are many square 

micrometers large. The thickness of each 

Atomic resolution STM image of graphite 

(HOPG) 

sheet is less than 1 nm. Image courtesy: 

Dr. Hannes Schniepp (The College of William & Mary, USA)

Nanowire 

Light Transport studies with NTEGRA Spectra 

Fibeer 

probe 

(X,YY,Z 

scan) 

EExcitation it ti points i t 

Laser excitation B 

Edge filter 

Collected light 

AFM A probe (X,Y,Z scan) 

Detection point 

Sample (on X,Y,Z-stage) 

High NA 100x objective 

(Z-movable) 

Laser excitation A 

X,Y,Z-movable objective 

Pinhole: adjustable (0-2 mm) & X,Y-movable 


To light registration: 

Excitation point 

` 

Emission from ends 

Emission from end 

Excitation point

Emission from end 

Light Transport studies with NTegra Spectra 

Excitation point 

NNanowire i iis llocally ll excited it d at t the th bbottom tt end. d RRed d curve shows h 

fluorescence spectrum taken at the excitation point. Blue curve is the 

transmitted light spectrum taken at the upper end of the nanowire. Green 

curve shows spectral transmission function of the nanowire 

NTEGRA Spectra

Beta-carotene distribution in algal cells 

Optical image Confocal Laser AFM topography 

Sample courtesy of Don McNaughton, 

Monash University, Australia 


β-carotene Raman band 

Tail of luminescence 

(centered at ~630 630 nm)

Beta-carotene distribution in algal cells 

Optical microscope image 

(with 100x objective) 

Image size: 

25x25 µm 

Confocal laser image AFM-image 

Raman map (ß-carotene) Luminescence map 


Magnetic Magnetic-, 

Kelvin-, 

Electrostatic- 

Acoustic Force- Force 

Capacitance – 

Spreading resistance … 

Scanning Probe images

Malaria infected red blood cell, AFM-Raman 

AFM topography Raman map 

C Raman spectra 

Hemozoin Hemoglobin 

AFM image of a trophozoite iRBC and a false color 3-cluster UHCA map of the same cell generated from 

the Raman spectra. Mean cluster spectra from the two clusters associated with hemozoin (blue) and 

hemoglobin (green) are shown. This fixation protocol preserved the structural integrity of the iRBC and 

sub-micron sized knobs can be seen on the surface of the cell in the AFM image. 

The size of these knobs were 20-50 nm in height and 100-150 nm in width which is the same as values 

previously reported and measured by SEM, TEM, and AFM. 

NTEGRA Spectra Data courtesy: Don MacNaughton, Monash Univ.

Polymer sample with protective cover layer - depth profile 

Raman spectrum versus sample depth 

Sample 

deepth, 

�m 

Raman shift 

Two layers are observed. 

The 2nd layer is 500 nm below the first layer 

and has a characteristic Raman line (620 cm 


-1 ) 

Layer #2 

Layer #1 

Zoomed region 

0.5 �m

AFM -> 

Scan size: 40 x 40 µm 

Raman -> 

Polymer blend 

NT-MDT NTEGRA Spectra + Renishaw Raman microscope

NT-MDT + Renishaw INTEGRATED system 

Advertising leaflets of the Integrated system (issued by Renishaw and by NT-MDT)

NT-MDT + Renishaw INTEGRATED software 

1. Renishaw measurement setup 

menu is opened and 

controlled from NT-MDT NT MDT 

NOVA software 

2. NT-MDT software FULLY 

controls the AFM-Raman 

experiment (except rare 

adjustments j or calibrations of 

the system) 

NTEGRA Spectra

NT-MDT + Renishaw INTEGRATED software 

EXACTLY THE SAME DATA in two programs: NT-MDT & Wire-3 

All scans can be seen and analyzed in any software: AFM (height, phase etc) & Raman 

maps. Data from NT-MDT Nova was exported into WIRE-3

Tip Enhanced Raman Scattering (TERS) 

A route to Raman microscopy py with subwavelength g spatial p 

resolution and single molecule sensitivity 

TERS – “inverted” SERS effect (scanning metal tip is a HOT SPOT) 

Electromagnetic field 

intensity around 

metal tip 

2RR) 


200-600 nm 

Metal AFM probe 

Enhanced Raman 

signal 

Focused laser spot

NT-MDT provides all possible AFM/Raman/TERS configurations 

INVERTED UPRIGHT Side illumination + UPRIGHT 

excitation 

TERS collection 


excitation 

TERS collection E 

excitation 

Different probe types and feedback mechanisms: 

AFM (contact, intermittent contact), STM, Tuning fork (normal force and shear force) 

Dual scan: 6 piezodriven coordinates (“laser + sample” or “tip + sample”)

Tip Enhanced Raman 

INVERTED geometry (transparent samples) 

Sh Shear fforce

To find HOT POINT (Maximum enhancement): 

Scan - BY TIP; Measure - intensity of laser light scattered by the tip 

E 

200 nm ____ 

HHot t point i t ! 

Metal AFM probe 

xy&z-scan 

x,y & z scan 

Focused laser spot 

Etched Au wire 

1. Scan (XY&Z) by tip across 

the laser spot. p 

Measure Raman or Rayleigh 

scattered light 

2. Position tip inside “hot point” 

with high precision 

Scan by the sample to get 

TERS map 

Data courtesy of S. Kharintsev, J. Loos, G. Hoffman, G. de With, TUE, the Netherlands and P. Dorozhkin, NT-MDT

TERS imaging of single-walled CNT bundle 

__ 200 nm 

Tip is away 

__ 200 nm 

Tube image width 

AFM topography 

is 

(h (height i 

~250 

ht 

250 

~ 5 

nm 

nm) ) 

(limited by 

wavelength of light) 

Raman map 

(G-line) 

Tip p is approached 

pp 

Laser: 633 nm 

Tube image width is 

Tip: Etched gold wire ~50 nm (limited ( 

only by size of the tip) 

S.S. Kharintsev, G. Hoffmann, P.S. Dorozhkin, 

G. de With, and J. Loos 

Nanotechnology 18 (2007), 315502 

Raman spectra and 2D confocal Raman maps (G (G-line) line) of carbon nanotube 

rope with and without enhancing AFM tip (GOLD wire) 

NTEGRA Spectra

TERS with Silver coated cantilevers 

AFM image of carbon nanotube 

bundle 

Scan size: 2x3 micron 

TERS image of the same 

bundle 

Image courtesy: Jacon Jao, Jao Renato Zenobi ETH Zurich, Zurich Switzerland; GG. 

Hoffman, J. Loos, TUE, Eindhoven; and Pavel Dorozhkin, NT-MDT Russia 


`

Tip Enhanced Raman 

UPRIGHT geometry t (non-transparent ( t t samples) l ) 

100x 

0.7 NA 

TERS excitation 


0.7 NA 

45° 

100 100x TERS collection ll ti 

0.7 NA 

E 

excitation

Looking for Hot Spot – 

laser beam is scanned across the cantilever 

0.7 NA 

45° 

Laser scanning module allows to position laser beam precisely at the apex of AFM 

tip and fix it there - thanks to closed-loop operation of the scanning mirror

TERS in UPRIGHT geometry – Graphene 

Finding g HOT SPOT on AFM tipp 

Raman spectra from Graphene flake: 

--- Inside “hotspot” 

--- Outside “hotspot” hotspot 

--- Signal from tip (sample is removed) 

Data from: A. Schokin & 

PP. Dorozhkin Dorozhkin, NT‐MDT 

Laser beam is scanned across cantilever tip 

Raman signal from substrate measured 

cantilever

TERS on periodic Si-Ge structure, resolution ~50 nm 

Data courtesy: Dr. Peter Hermann et at., Fraunhofer CNT & AMD, Dresden 

TERS tool evaluation project, AMD Dresden & NT-MDT

Successful Tip Enhanced Raman experiment: 

Major requirements to experimental setup (AFM – Raman combination) 

1. Different geometry of AFM and high resolution Raman optics: bottom 

illumination/collection, top illumination/collection, side illumination/ top 

collection. 

2. Dual scan option (6 closed loop piezo coordinates): sample+laser 

scanning OR sample+tip scanning 

3. All AFM and Raman control must be integrated into one software package 

4. Very y low AFM noise (to ( keep p TERS tip p safely y very y 

close to sample), low drifts and high stability 

(to keep laser exactly on the hot 

spot p – with 10 nm precision) p ) 

5. Good TERS tip

SCANNING NEAR-FIELD OPTICAL MICROSCOPY 

Straight quartz fiber with 

aperture (glued to tuning fork) 

Silicon cantilevers with 

aperture 

100x, 0.7 NA 

All SNOM modes are available: 

Collection, Transmission, Reflection 

(for all signals/modes: laser, fluorescence and spectroscopy)

AUTOMATIC alignment of laser spot and SNOM aperture 

laser spot is scanned: xx,y y Intensity of light transmitted 

through cantilever 

Precise location of SNOM aperture 

___ 10µm 

Laser spot is scanned in automatic regime across SNOM cantilever and transmitted 

signal is measured – to locate the SNOM aperture with very high accuracy (

SNOM transmission: Single lipofuscin granule 

Shear force topography SNOM transmission 

Single lipofuscin granule 400 nm in height and 1.7 – 2.7 µm in 

diameter. Two “humps” can be seen as well at shear-force image 

(left one). one) On the right image transmission at 420 nm can be seen seen. 

Quartz substrate transmission was subtracted so negative values can 

be referred to sample absorption and positive ones (most probably) 

to sample fluorescence. 

NTEGRA Spectra

SNOM spectroscopy: Single lipofuscin granule 

Point-localized spectroscopy of putative fluorescent region. The 

spectrum obtained corresponds well with the spectrum of pure 

A2E fluorophore thought to be the major cause of aging-related 

retina degeneration 

degeneration. 

NTEGRA Spectra

SNOM on photonic SNOM Lithography crystal performance optical fibers 


Overlay of simultaneously measured: 

Sample topography (orange/red palette) and 

SNOM intensity (green palette) 

Data courtesy: 

Yinlan Ruan, Heike Ebendorff-Heidepriem, Tanya M. Monro 

Centre of Expertise in Photonics Photonics, School of Chemistry & 

Physics, University of Adelaide, Adelaide, 5000 Australia

SNOM measurements (VIS & IR) : Cr:YAG optical fibers

SNOM on Surface Plasmon Polaritons 

Data from: 

Antonell Nesci and Olivier J.F. Martin, 

EPFL, Lausanne, Switzerland

SNOM on Surface Plasmon Polaritons 

Data from: 

Antonell Nesci and Olivier JJ.F. F Martin Martin, 

EPFL, Lausanne, Switzerland



AFM – Raman – SNOM in controlled environment

SNOM 

AFM + Raman + SNOM in LIQUID 

AFM 

NT-MDT Closed-liquid cell with heating 

Possible to use with AFM + SNOM + Confocal Raman (Confocal 

fluorescence), ), work with living g cells. Flow-trough g ppossibility. y 

WORKS WITH AFM/SNOM/ RAMAN (INVERTED) 

NTEGRA Spectra

AFM – Raman – SNOM in Upright configuration in liquid 

100x 

100x 

NA = 1 

NA = 1 

280 nm 

- NA=1 (120º) 

2 mm 

280 nm 

- TERS in liquid for opaque samples 

- Cantilever based SNOM in liquid

Electrochemical cell for AFM – Raman in external magnetic field 

AFM quartz nose 

EC cell 

Transparent sample 

Cantilever 

objective 

• Microscope configuration: Inverted 

• Objectives used: any objective (Olympus, 

Nikon) 

• AFM modes in liquid: contact, noncontact 

• Sample: transparent (ITO, quartz with 

thin metal layer etc.) 

• Stabilized temperature p (-10º ( - +60º) ) 

• External magnetic field (up to 0.2 T) 


EC cell 

objective

Ultra Stable AFM – Confocal Raman – TERS measurements 

in wide temperature range 

T = -30 - +80 ºC 

Drifts < 10 nm per 1ºC 1C < 10 nm per hour at all temperatures 

Couunts 

3000 

2750 

2500 

2250 

2000 

1750 

1500 

1250 

1000 

750 

500 

Raman spectra of Graphene 

flake at T = -20, , +20, , +80 ºC 

Raman spectrums vs temperature 

T=25 C 

T= 80 C 

T= -20 C 

1400 1800 2200 2600 3000 

1200 1600 2000 2400 2800 3200 

Raman shift, cm-1

AFM-Raman-SNOM-TERS in CONTROLLED ATMOSPHERE 

Controlled atmosphere chamber for AFM-Raman-TERS 

(controlled temperature, humidity, inert gases etc.) 

NTEGRA Spectra

Modes 

NT MDT integrates 

AFM, SNOM, Confocal Raman/Fluorescence and TERS 

in one device 

• AFM (mechanical, electrical, magnetic properties 

and nanomanipulation – more than 30 modes) 

• White Light Microscopy and Reflected Laser 

(Rayleigh) Confocal Imaging 

• Confocal Raman Imaging and Spectroscopy 

• Confocal Fluorescence Imaging g g and 

Spectroscopy 

• Scanning Near-Field Optical Microscopy 

• Tip Enhanced Raman and Fluorescence 

Microscopy (TERS, TEFS) 

www.ntmdt.com/device/ntegra-spectra 

Controlled environment 

•Temperature 

•Humidity 

•Gases 

•Liquid 

•Electrochemical environment 

•External magnetic field 

Contact : Dr. Pavel Dorozhkin, dorozhkin@ntmdt.com

AFM â€“ Confocal Raman â€“ SNOM and Tip Enhanced Raman ...

Create successful ePaper yourself

Delete template?

Save as template?