Figure 1: Tip Enhanced Raman Scattering spectra obtained with the Nanonics TERS probe tipped with a gold nanoparticle.

The plot shows a far-field Raman spectrum of 15nm strained silicon layer on silicon bulk (black) and the near-field enhanced Raman spectrum when the tip is in contact with the strained silicon.

The graph shows a large enhancement of the strained peak (515 cm-1) with reference to the far-field spectrum.

The enhancement above is obtained with the accurate tip positioning option through the tip-scanning mode to obtain efficient off-axis enhancement.

Figure 2: Raman maps of the Raman intensity of the 520cm-1 (A) and 515cm-1 (B) bands obtained in tip-scanning of a 532nm laser spot.

The images show the Raman maps of the strained silicon layer on a silicon bulk sample obtained with AFM/Raman imaging using a Nanonics TERS probe (tipped with a gold nanoparticle).  (Blue indicates lowest intensity and red indicates highest intensity.)

Probe: Nanonics' TERS cantilevered probe tipped with a gold nanoparticle. The Nanonics' TERS probe allows for a clear optical axis for backscattered Raman through an upright optical microscope.

An upright microscope with a 50x objective has been used to illuminate the sample with a 532nm laser. 

The MultiView 2000^TM SPM head has been used in tip-scanning mode for an AFM/Raman scan of the laser spot area.

Figure 2A shows the Raman intensity of the 520 cm-1 Si band.
A uniform intensity can be seen surrounding the blue area (due to the tip shadow).

Figure 2B shows the Raman intensity of the 515 cm-1 sSi band. The maximum enhancement is seen when the gold nanoparticle probe approaches the Z polarization lobe of the laser beam.